银纳米粒子熔化的尺寸效应研究

采用分子动力学方法对银纳米粒子进行了熔化过程的模拟,研究分析了银纳米粒子熔化的尺寸效应问题。仿真结果表明,银粒子固-液相变时,其系统势能在某一温度范围内具有明显的突变,熔化过程类似于非晶体,并且银纳米粒子的熔化温度明显低于块状材料,随着纳米粒子尺寸的减小,其熔点也随之降低,根据仿真结果及理论分析建立了纳米粒子熔点与粒径之间的数值关系,并分析了相关的主导机制。

Size Effect of Melting of Silver Nanoparticles

In order to study the size effect of melting of silver nanoparticles, the melting process of silver nanoparticles of different sizes were simulated by molecular dynamics in this paper. Simulation results show that the system potential energy has an obvious mutation within a certain temperature range when solid state transforms into liquid state, which is similar to amorphous body. And, the melting temperature of nanoparticles is significantly lower than that of the bulk materials and the melting point decreases with the reduction in the size of nanoparticles. The dominant mechanism and the relationship between melting point and nanoparticle size were also analyzed.