About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Ceramic Materials and Processing
|
| Presentation Title |
Phase Identification in the RE2O3-REPO4 Systems: RE=Y and Yb |
| Author(s) |
Elizabeth J. Opila, Seungyun Ryu |
| On-Site Speaker (Planned) |
Elizabeth J. Opila |
| Abstract Scope |
Rare earth (RE) oxyphosphate systems contain a host of intermediate high temperature phases with compositions between the sesquioxide (RE2O3) and orthophosphate (REPO4) that show promise for high temperature environmental barrier coating applications. However, many of these intermediate phases are unknown. Efforts to identify, synthesize, determine structures, and properties of these phases are underway. In this presentation, two experimental methods are described. Firstly, Y oxyphosphates were exposed to high-velocity 1500°C steam for 100h depleting P2O5 as a volatile phosphorous hydroxide, producing porous layered reaction products that correspond to the equilibrium intermediate compounds. Y14P4O31 exposures resulted in a double layer of reaction products with the first corresponding to Y:P of about 5.5 overlaid with Y2O3. Secondly, Yb2O3-YbPO4 diffusion couples exposed at 1500°C for times up to 100h resulted in two intermediate phases with Yb:P ratios varying between 3.5 and 6. Current status of known rare earth oxyphosphate phases will be described. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Ceramics, Phase Transformations, |