Fabrication of FeCoNi medium-entropy alloy nanoparticles by high-repetition-rate UV picosecond laser ablation in water
Fabrication of FeCoNi medium-entropy alloy nanoparticles by high-repetition-rate UV picosecond laser ablation in water
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DOI：
10.1016/j.jallcom.2023.169896
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发表时间：
2023-03
影响因子：
6.2
通讯作者：
A. Watanabe;T. Yatsuhashi
中科院分区：
文献类型：
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作者：
A. Watanabe;T. Yatsuhashi
液体中的激光烧蚀（LAL）是一种快速加热和冷却过程，可以形成各种纳米材料。已经报道了对金属、半导体、绝缘体和碳的广泛LAL研究。此外，合金是值得研究LAL适用性的目标。我们报告了在水中等原子FeCoNi中熵合金（MEA）的LAL使用高重复率的紫外皮秒激光与振镜扫描仪。的胶体溶液，形态，元素组成，和MEA纳米粒子（NP）的尺寸分布的消光光谱进行了研究作为激光照射时间，激光功率和扫描速度的函数。电子显微镜显示，形成了由直径约50 nm的富Ni FeCoNi MEA核Fe壳球形纳米粒子组成的长于10 µm的链状超结构。这些超结构不是起源于样品制备过程中的NP团聚显微镜或连续的激光照射的胶体，但从靶表面上的overstriking烧蚀。通常，LAL目标由空间和时间上分离的近红外或可见光激光脉冲照射以有效地产生NP。紫外超短激光脉冲的照射被证明是一种有价值的策略，用于修改MEA纳米颗粒的元素组成和形成它们的超结构。
Laser ablation in liquid (LAL) is a rapid heating and cooling process that enables the formation of a variety of nanomaterials. Extensive LAL studies for metals, semiconductors, insulators, and carbons have been reported. Further, alloys are worthwhile target to investigate the applicability of LAL. We report the LAL of equiatomic FeCoNi medium-entropy alloy (MEA) in water using a high-repetition-rate UV picosecond laser with a galvanometric scanner. The extinction spectra of the colloidal solution, morphology, elemental composition, and size distribution of MEA nanoparticles (NPs) were investigated as a function of laser-irradiation time, laser power, and scanning speed. Electron microscopy revealed that chain-like superstructures longer than 10 µm consisting of Ni-rich FeCoNi MEA-core Fe-shell spherical NPs of approximately 50-nm diameter were formed. These superstructures were not originated from the NP agglomeration during sample preparation for microscopy or the successive laser irradiation of colloids, but from the overstriking ablation on the target surface. Generally, the LAL target was irradiated by spatially and temporally separated near-infrared or visible laser pulses to efficiently produce NPs. Overstriking of UV ultrashort laser pulses was shown to be a valuable strategy for modifying the elemental composition of MEA NPs and for forming their superstructures.