Publication Date:
2019
Description:
Abstract
Investigated presently is how rare‐earth element dopants (samarium and erbium) affect the scale development of sintered ZrB2/SiC (ZBS) samples during ablation testing. 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 60s and 300s 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.
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Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
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