Spherical Particle Formation Mechanism in Pulsed Laser Melting in Liquid under Controlled-Pulse-Number Irradiation using a Slit Nozzle Flow System
Spherical Particle Formation Mechanism in Pulsed Laser Melting in Liquid under Controlled-Pulse-Number Irradiation using a Slit Nozzle Flow System
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DOI：
10.1021/acs.jpcc.9b06949
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发表时间：
2019-10-10
影响因子：
3.7
通讯作者：
Sakaki, Shota
中科院分区：
文献类型：
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作者：
Ishikawa, Yoshie;Koshizaki, Naoto;Sakaki, Shota
脉冲激光熔化液体(PLML)的详细机制一直是一个有争议的问题，因为在传统的间歇式照射中，跟踪和观察特定脉冲数量的粒子存在困难。在之前的研究中，我们开发了一种带有新型狭缝喷嘴的流动辐照技术，用于PLML的大规模生产。狭缝喷嘴可以精确地控制照射到流经狭缝喷嘴的颗粒上的脉冲数。在本研究中，狭缝喷嘴的这一独特特性被用来通过特定脉冲数的照射来阐明PLML的机制。根据对缝隙喷嘴流动的数值分析，79%的流经缝隙喷嘴的颗粒被两个或三个脉冲照射，其他颗粒在体积流量为1.1mL.S(-1)的体积流量下通过缝隙喷嘴时被三个或三个以上的脉冲辐照，用于悬浮在60wt%甘油水溶液中。通过少脉冲辐照聚集体，形成了亚微米级的中空球形颗粒。空心颗粒形成后，随着激光脉冲数的增加，空心颗粒中的空洞消失。因此，首次使用狭缝喷嘴观察到了具有特定辐照脉冲数的球形粒子的初始形成过程和粒子的形态转变。还跟踪了激光脉冲照射下Fe3O4颗粒的还原作为流动通道的函数。
A detailed mechanism of pulsed laser melting in liquid (PLML) has remained a controversial issue because of the difficulty associated with tracking and observing particles irradiated with a specific number of pulses in conventional batch-style irradiation. In a previous study, we developed a flow irradiation technique with a new slit nozzle for PLML mass-production. The slit nozzle can precisely control pulse numbers irradiated onto particles flowing through the slit nozzle. In the present study, this unique feature of the slit nozzle was used to clarify the PLML mechanism by a specific pulse number irradiation. According to a numerical analysis of the flow with the slit nozzle, 79% of the particles flowing through the slit nozzle were irradiated with two or three pulses and other particles that were irradiated with three or more pulses upon one passage through the slit nozzle at a 1.1 mL s(-1) volume flow rate for a particle suspension in 60 wt % glycerol aqueous solution. Sub-micrometer-sized hollow spherical particles were formed via few-pulse irradiation of aggregates. After hollow particles were formed, the void in the hollow particles disappeared with increasing laser pulse number. Thus, an initial process of spherical particle formation and morphological transition of the particles with a specific irradiated pulse number were observed for the first time using the slit nozzle. The reduction of Fe3O4 particles via laser pulse irradiation was also tracked as a function of flow passage.