Metal nanoparticles generated by laser ablation
Metal nanoparticles generated by laser ablation
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DOI：
10.1016/s0965-9773(98)00121-4
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发表时间：
1998-07-01
期刊：
影响因子：
--
通讯作者：
Glicksman, HD
中科院分区：
文献类型：
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作者：
Becker, MF;Brock, JR;Glicksman, HD
我们研究了一种新的方法来生产超细金属颗粒（纳米颗粒），采用激光烧蚀微粒（LAM）。在正常大气条件下以及在其他气体和压力下，使用248 nm波长的脉冲准分子激光辐射来烧蚀类似于2 μ m原料的银、金和坡莫合金（Ni-81%：Fe-19%）。提出了一个纳米粒子形成的LAM模型，其中包括等离子体击穿和冲击波通过初始微粒的传播。在冲击波之后，原始微粒质量的很大一部分被转化为纳米颗粒，纳米颗粒扩散到硅衬底和TEM网格上进行收集和分析。纳米颗粒形态是球形的，除了大于100 nm的金纳米颗粒通常是立方体。通过计算机辅助图像处理分析样品的电子显微照片，以确定照射条件对纳米颗粒尺寸分布的影响。结果表明，平均粒径通常在10至100 nm的范围内，粒径分布通常为对数正态分布，分散度（直径/标准偏差）为0.2至0.5。对于金属微粒原料，所产生的纳米颗粒的平均尺寸通常随着激光能量密度的增加而增加，并且对于不太远高于击穿阈值的能量密度是最小的。(C)1998年冶金学报
We study a new method for producing ultrafine metal particles (nanoparticles) that employs Laser Ablation of Microparticles (LAM). Pulsed excimer laser radiation at 248 nm wavelength was used to ablate similar to 2 mu m feedstock of silver, gold, and permalloy(Ni-81%:Fe-19%) under both normal atmospheric conditions and in other gases and pressures. A model for nanoparticle formation by LAM is proposed that includes plasma breakdown anal shock-wave propagation through the initial microparticle. Behind the shock a large fraction of the original microparticle mass is converted to nanoparticles that diffuse to silicon substrates and TEM grids for collection and analysis. Nanoparticle morphologies are spherical except for gold nanoparticles >100 nm that are generally cubes. Electron micrographs of the samples were analyzed by computer-aided image processing to determine the effect of irradiation conditions on the nanoparticle size distribution. The results showed that mean particle diameters were normally in the range from 10 to 100 nm and that the particle size distributions were generally log-normal, with dispersion (diameter/standard deviation) ranging from 0.2 to 0.5. For metallic microparticle feedstock, the mean size of the produced nanoparticles generally increased with increasing laser fluence and were smallest for fluences not too far above the breakdown threshold. (C) 1998 Acta Metallurgica Inc.