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A General Synthesis Strategy for Volatile-Element-Based Compounds: Achieving Near-Zero Thermal Expansion and Advanced Microwave Absorption in Yb2Fe17 and its Nitride
T
L
S
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韩
C
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B
K
林
R
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DOI:10.1016/j.actamat.2026.122639.png)
Abstract
En 中文
The synthesis of ytterbium (Yb)-based intermetallic compounds via conventional physical methods has been substantially hindered by the pronounced volatility of ytterbium, impeding both fundamental magnetic studies and practical implementations. This study develops an in-situ confined reduction-diffusion (IC-RD) strategy coupled with compaction-encapsulation technology, effectively mitigating the evaporation of ytterbium. This method successfully yields high-purity Yb2Fe17, which is subsequently converted into Yb2Fe17N3-δ via nitridation. Neutron powder diffraction (NPD) analysis reveals a near-zero thermal expansion (near-ZTE) behavior in Yb2Fe17, characterized by an ultralow volumetric thermal expansion coefficient (αv) of 1.6 × 10-⁷ K-¹ within the 100-250 K temperature range. Furthermore, nitriding significantly enhances the magnetic properties, leading to a higher magnetic ordering temperature and large saturation magnetization in Yb2Fe17N3-δ. When incorporated into a paraffin composite, Yb2Fe17N3-δ exhibits outstanding microwave absorption performance, achieving a minimum reflection loss (RLmin) of -50.5 dB at 3.37 GHz in the S-band with a matching thickness of 4.8 mm. In contrast, the maximum effective absorption bandwidth (EABmax) reaches 5.96 GHz at a thinner thickness of 1.4 mm, mainly in the Ku-band. This study not only establishes a viable synthetic pathway for compounds containing highly volatile elements, but also opens avenues for designing materials with tailored structural and magnetic properties, as well as advancing thin-layer broadband microwave absorbers.
Keywords:
reduction-diffusion
high volatility
Yb2Fe17
near-zero thermal expansion
Yb2Fe17N3-δ
microwave absorption
Journal
IF:
9.3
Papers:
2.0W
Citations:
12.9W
