Controllable Negative Thermal Expansion by Mechanical Pulverizing in Hexagonal Mn0.965Co1.035Ge Compounds
Controllable Negative Thermal Expansion by Mechanical Pulverizing in Hexagonal Mn0.965Co1.035Ge Compounds
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六方Mn0.965Co1.035Ge化合物机械粉碎可控负热膨胀
DOI：
10.1021/acs.inorgchem.8b02195
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发表时间：
2018
影响因子：
4.6
通讯作者：
Zhong Zhenchen
中科院分区：
文献类型：
--
作者：
Yang Sheng;Ma Shengcan;Liu Kai;Hu Yongfeng;Yu Kun;Han Xingqi;Zhang Zhishuo;Song Ying;Chen Changcai;Luo Xiaohua;Wang Dunhui;Zhong Zhenchen
负热膨胀（NTE）材料作为一种补偿材料，对于精确控制材料的热膨胀非常重要。沿着热膨胀系数的大小，NTE材料的工作温度窗口也是主要关注点。然而，只有少数NTE材料同时具有大的工作温度范围和大的热膨胀系数。为了探索这类新型NTE材料，采用机械球磨法制备了Mn0.965Co1.035Ge超细粉体。这些细粉显示出很大程度上扩展的NTE操作温度窗口，同时具有巨大的热膨胀系数。对于BM-0.5h、BM-4 h和BM-12 h等不同BM时间处理的样品，其工作温度窗口（ΔT）和线性热膨胀系数（αL）为167 K（222-389 K）和100 - 63 ppm/K，221 K（140-360 K）和100 - 41.3 ppm/K，以及208 K（234-442 K）和100 - 40 ppm/K，这些都大于大多数已知的NTE材料。更引人注目的是，所有BM样品具有大的恒定线性NTE系数，具有覆盖室温的超宽温度窗口。对于这三个样本，这些值分别为<$−52 ppm/K（140 K）、<$−58.3 ppm/K（110 K）和<$−65 ppm/K（80 K）。基于热磁测量和X射线吸收光谱结果，讨论了该材料优良NTE性能的来源。
Negative thermal expansion (NTE) material as a compensator is very important for accurately controlling the thermal expansion of materials. Along with the magnitude of the coefficient of thermal expansion, the operating temperature window of the NTE materials is also a major concern. However, only a few of the NTE materials possess both a large operating temperature range and a large thermal expansion coefficient. To explore this type of new NTE material, the Mn0.965Co1.035Ge fine powders were prepared by mechanical ball milling (BM). These fine powders show a largely extended NTE operation temperature window simultaneously possessing a giant thermal expansion coefficient. For samples treated with different BM times, such as the BM-0.5h, BM-4h, and BM-12 h samples, the operating temperature window (ΔT) and linear thermal expansion coefficient (αL) are 167 K (222–389 K) and ∼ −63 ppm/K, 221 K (140–360 K) and ∼ −41.3 ppm/K, and 208 K (234–442 K) and ∼ −40 ppm/K, respectively, which are larger than most well-known NTE materials. More strikingly, all BM samples have a large constant linear NTE coefficient with an ultrawide temperature window covering room temperature. For these three samples, these values are ∼ −52 ppm/K (140 K), ∼ −58.3 ppm/K (110 K), and ∼ −65 ppm/K (80 K), respectively. The origin of the excellent NTE properties is discussed based on the thermomagnetic measurements and X-ray absorption spectroscopic results.