Abstract
In the pseudo binary system ZrO2-YOF included in the ZrO2-YF3-Y01.5 ternary system, samples of 3.0~7.7 mol% YOF within the region of tetragonal single phase at 1300°C were isostatically hot-pressed at 1200°, 1300° and 1450°C under 200 MPa for 3 h after encapsulating into Pt capsule to avoid compositional changes. Only for ZrOa-7.7 mol%YOF, metastable tetragonal zirconia single phase was obtained as a sintered body. For the other samples (<7.7 mol%YOF) whole or most of the tetragonal phase transformed diffusionlessly to monoclinic phase during cooling. X-ray study showed that the unit cell of the tetragonal phase has larger axial ratio (c/a), and that of the monoclinic phase was more distorted (larger ß) than that in the Zr02-Y01.5 system. According to the measurement by DTA on encapsulated specimens, the tetragonal phase in the ZrO2-YOF system transformed at higher temperatures than that in the ZrO2-Yo1.5 system. This seems to be caused by more distorted cells of the tetragonal and the monoclinic phases as the result of F- doping. Stress induced transformation was confirmed for the metastable tetragonal phase of this YOF doped zirconia.
| Original language | English |
|---|---|
| Pages (from-to) | 441-444 |
| Number of pages | 4 |
| Journal | Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy |
| Volume | 34 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - 1987 |
All Science Journal Classification (ASJC) codes
- Mechanical Engineering
- Industrial and Manufacturing Engineering
- Metals and Alloys
- Materials Chemistry