Low Thermal Expansion Modulated by Off-Stoichiometric Effect in Nonstoichiometric Laves Phase Hf0.87Ta0.13Fe2 x Compounds
Low Thermal Expansion Modulated by Off-Stoichiometric Effect in Nonstoichiometric Laves Phase Hf0.87Ta0.13Fe2 x Compounds
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非化学计量 Laves 相 Hf0.87Ta0.13Fe2 x 化合物中非化学计量效应调节的低热膨胀
DOI：
10.1021/acs.inorgchem.9b02989
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Sun Y.
中科院分区：
文献类型：
--
作者：
Li L;Tong P;Tong W;Jiang W;Ding Y;Lin H;Lin J;Yang C;Zhu F;Zhang X;Zhu X;Song W;Sun Y.
Materials with a low coefficient of thermal expansion (CTE) are extremely demanded in many fields, varying from microelectronics to space technology. Here we report a novel method to achieve low CTE, which differs essentially from the conventional way that uses additives with negative thermal expansion (NTE) to compensate for the positive CTE of the matrix. The stoichiometric Hf0.87Ta0.13Fe2+x(x= 0) shows a giant NTE, which is gradually suppressed with increasingxand finally changed to near-zero thermal expansion (ZTE) atx≈ 0.4. The excess Fe was suggested to form anti-site defects by occupying the 4f sites. As revealed by electron spin resonance (ESR) spectra, the weakened NTE is closely related to a slower ferromagnetic (FM) ordering process than observed atx= 0. In addition, the CTE can be further tuned by introducing an extra α-Fe phase to achieve a low CTE (e.g., 3.3 ppm/K forx= 1.0) with markedly enhanced mechanical properties, beneficial to applications.
