Dissolution of Yttrium Ions and Phase Transformation of 3Y-TZP Powder in Aqueous Solution
Resource
Journal of the American Ceramic Society 82 (6): 1614-1616
Journal
Journal of the American Ceramic Society
Journal Volume
82
Journal Issue
6
Pages
1614-1616
Date Issued
1999
Date
1999
Author(s)
Ho, Fang-Yuan
Abstract
In order to understand the reactions of yttria-containing zirconia powder in aqueous solution, the dissolution behavior of yttrium and the formation of the monoclinic (m) phase of the Y-TZP powder were investigated. The tests were conducted in aqueous solution at temperatures up to 95°C. The results showed that the reaction order of yttrium dissolution from the surface of TZP powder is 5-9, and the activation energy is about 8.4 kJ/mol. However, the value of the reaction order is different from that (0.96-1.20) of the formation of m-phase. However, the yttrium dissolution of the slurries with the addition of 2 mol% dispersant (D-134) was reduced greatly to an extremely low (<2 ppm) level up to 24 h at the testing temperatures. The results also showed that the amounts of m-phase formation were nearly the same for the powders in the slurries with or without D-134 addition. The decrease of yttrium content in the presence of D-134 and the formation of the m-phase of the TZP powder were not closely related. The degradation mechanism, or the formation of m-phase, should not be directly related to the dissolution of yttrium ions from a zirconia surface.
Other Subjects
Activation energy; Ceramic materials; Dissolution; Phase transitions; Powders; Solutions; Surfaces; X ray diffraction analysis; Yttrium; Monoclinic phase; Yttria containing zirconia; Zirconia
Type
journal article
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