Determining the Composite Structure of Au-Fe-Based Submicrometre Spherical Particles Fabricated by Pulsed-Laser Melting in Liquid
Determining the Composite Structure of Au-Fe-Based Submicrometre Spherical Particles Fabricated by Pulsed-Laser Melting in Liquid
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DOI：
10.3390/nano9020198
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发表时间：
2019-02-01
期刊：
影响因子：
5.3
通讯作者：
Swiatkowska-Warkocka, Zaneta
中科院分区：
文献类型：
--
作者：
Fuse, Hokuto;Koshizaki, Naoto;Swiatkowska-Warkocka, Zaneta
以Au和氧化铁纳米粒子为原料，分散在乙醇中，通过脉冲激光液相熔融（PLML）制备出了由Au和Fe组成的亚微米球形粒子，但详细的形成机理还不清楚。利用355 nm脉冲激光避免了两种不同原料颗粒在激光照射过程中的极端温差，以Fe 2 O3原料纳米颗粒胶体溶液作为铁源促进Au和Fe 2 O3纳米颗粒的聚集，对产物进行了深入表征，阐明了Au-Fe复合亚微米球形颗粒的形成机理。由于上述两种措施（Fe 2 O3原始纳米颗粒和355 nm脉冲激光），产品-无论是相分离的颗粒还是均匀的合金-基本上遵循相图。在富铁范围内，形成相分离的Au核/Fe壳颗粒，因为淬火诱导富铁组分的早期固化，作为从周围的乙醇冷却的结果。如果颗粒尺寸小，则淬灭速率变得非常快并且颗粒较少相分离。对于高Au含量超过70%的重量，形成结晶的富Au合金没有相分离。因此，需要这种聚集控制以通过PLML选择性地形成均匀或相分离的较大亚微米尺寸的颗粒。
Submicrometre spherical particles made of Au and Fe can be fabricated by pulsed-laser melting in liquid (PLML) using a mixture of Au and iron oxide nanoparticles as the raw particles dispersed in ethanol, although the detailed formation mechanism has not yet been clarified. Using a 355 nm pulsed laser to avoid extreme temperature difference between two different raw particles during laser irradiation and an Fe2O3 raw nanoparticle colloidal solution as an iron source to promote the aggregation of Au and Fe2O3 nanoparticles, we performed intensive characterization of the products and clarified the formation mechanism of Au-Fe composite submicrometre spherical particles. Because of the above two measures (Fe2O3 raw nanoparticle and 355 nm pulsed laser), the products-whether the particles are phase-separated or homogeneous alloys-basically follow the phase diagram. In Fe-rich range, the phase-separated Au-core/Fe-shell particles were formed, because quenching induces an earlier solidification of the Fe-rich component as a result of cooling from the surrounding ethanol. If the particle size is small, the quenching rate becomes very rapid and particles were less phase-separated. For high Au contents exceeding 70% in weight, crystalline Au-rich alloys were formed without phase separation. Thus, this aggregation control is required to selectively form homogeneous or phase-separated larger submicrometre-sized particles by PLML.