Melting behavior of Ag nanoparticles and their clusters

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• 作者：Daili Feng^a ; Yanhui Feng^a ; ^b ; ^{yhfeng@me.ustb.edu.cn} ; Siwei Yuan^a ; Xinxin Zhang^a ; ^b ; Ge Wang^c
• 关键词：Nanoparticles ; Clusters ; Melting point ; Specific surface area ; Molecular dynamics
• 刊名：Applied Thermal Engineering
• 出版年：2017
• 出版时间：25 January 2017
• 年：2017
• 卷：111
• 期：Complete
• 页码：1457-1463
• 全文大小：2578 K
• 卷排序：111

文摘

The melting behavior of silver nanoparticles with diameter ranging from 2.4 nm to 5 nm was investigated by molecular dynamics simulation. The nanoparticles are easy to aggregate because of higher surface defects of single particle, and this limits the application of nanomaterials. The aggregation effects were further analyzed on the melting of sintered silver cluster. Expressions of melting point were achieved for single particle and particle cluster respectively, and are of the linear function of reciprocals of particle diameter. Results indicate that a decrease of specific surface area, due to the neck formation between particles with aggregation, leads to a rising of melting point for clusters. Minuscule silver particles approximately smaller than 2.8 nm in the diameter possibly melt at an abnormal higher temperature, when particles aggregate together to form one big size cubic nanoparticle. The clustering phenomena were observed in 100 nm silver nanopowder by X-ray diffraction and transmission electron microscope. The melting point of nanopowder was measured by thermal analyzer and shows a good agreement with simulated results for clusters.