Bulk Grain-Boundary Materials from Nanocrystals
Bulk Grain-Boundary Materials from Nanocrystals
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DOI：
10.1016/j.chempr.2020.12.026
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发表时间：
2021-02
期刊：
影响因子：
23.5
通讯作者：
Yasutaka Nagaoka;M. Suda;Insun Yoon;N. Chen;Hanjun Yang;Yuzi Liu;B. Anzures;S. Parman;Zhongwu Wan
中科院分区：
文献类型：
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作者：
Yasutaka Nagaoka;M. Suda;Insun Yoon;N. Chen;Hanjun Yang;Yuzi Liu;B. Anzures;S. Parman;Zhongwu Wan
晶界工程是充分利用各种材料的力学、电学和热输运特性的关键。然而，目前的冶金方法几乎完全依赖于自上而下的方法，使得精确的晶界工程，特别是在纳米尺度上，难以实现。在此，我们报告了一种通过表面处理和压力烧结工艺，从胶体金属纳米晶体中产生具有纳米级精度的定制晶界条件的方法。由此产生的块状晶界材料（我们称之为“纳米晶硬币”）具有类似金属的外观和导电性，同时继承了纳米晶构建块的原始域特征。纳米压痕测量证实了获得的材料具有优异的机械硬度。此外，我们首次用这种方法用非晶钯纳米颗粒制备了单组分大块金属玻璃。我们的发现可能会刺激新材料的发展，这些新材料的功能关键取决于纳米尺度上的畴结构，如超硬材料、热电发电机和功能电极。
Grain-boundary engineering is pivotal to fully utilize the mechanical, electrical, and thermal-transport properties of various materials. However, current methods in metallurgy rely almost exclusively on top-down approaches, making precise grain-boundary engineering, especially at nanoscale, difficult to achieve. Herein, we report a method to produce tailored grain-boundary conditions with nanoscale precision from colloidal metal nanocrystals through surface treatment followed by a pressure-sintering process. The resulting bulk grain-boundary materials (which we call "nanocrystal coins") possess a metal-like appearance and conductivity while inheriting the original domain features of the nanocrystal building blocks. Nanoindentation measurements confirmed the superior mechanical hardness of the obtained materials. Further, we use this method to fabricate, for the first time, a single-component bulk metallic glass from amorphous palladium nanoparticles. Our discovery may spur the development of new materials whose functionality crucially depends on the domain configuration at nanoscale, such as superhard materials, thermoelectric generators, and functional electrodes.