| Autor: |
Ho, Fang-Yuan, Wei, Wen-Cheng J. |
| Zdroj: |
Journal of the American Ceramic Society; June 1999, Vol. 82 Issue: 6 p1614-1616, 3p |
| Abstrakt: |
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 kJmol. 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. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
Plný text