Evaluation of rare‐earth element dopants (Sm and Er) on ablation resistance of ZrB2/SiC‐sintered billets
Abstract
In this paper, how rare‐earth element dopants (samarium and erbium) affect the scale development of sintered ZrB2/SiC (ZBS) samples during ablation testing was investigated. ZBS billets with five different Sm to Er ratios, with a nominal total amount of 3 mol% dopant incorporated, were prepared by sintering in vacuum to 2000°C and subjected to 60 and 300 seconds ablation cycles. Differences in surface temperatures between ZBS samples with different dopant ratios suggests differences in spectral absorptance/emittance between each of the five compositions investigated. ZBS billets co‐doped with Sm and Er form a beneficial c1‐(Sm/Er)0.2Zr0.8O1.9 oxide scale as the majority phase, with some glassy phase observed. The crystalline c1‐(Sm/Er)0.2Zr0.8O1.9 oxide scale is more thermally stable than the m‐ZrO2 oxide scale typically formed in oxidized ZBS systems, resulting in a more adherent oxide scale to the unreacted material. The crystalline oxide scale and the amorphous phase are formed by a convection cell mechanism where the c1‐(Sm/Er)0.2Zr0.8O1.9 crystalline islands precipitate, grow, and coalesce.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Mar 25, 2019
- Source ID
- 10.1111/jace.16422
Entities
People
- Angel A. Peña
- Jonathan P. Vernon
- Rodney W. Trice
Organizations
- Air Force Office of Scientific Research
- Air Force Research Laboratory
- Purdue University