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利用分子动力学方法和改进分析型嵌入原子势函数模拟了核-壳结构Ag-Au纳米颗粒的合金化行为,从原子扩散、微观结构演变以及合金化程度等方面对比分析了壳层厚度对合金化行为的影响。结果表明,壳层较薄时,核-壳界面处原子扩散现象显著,内核表现出多面体形貌,表层Au、Ag原子完全混合。壳层较厚时,表面原子以扩散为主,整个颗粒表面为多面体结构,但内核保持初始球状结构。通过层错生长方式使形貌发生了改变。壳层越薄,体系合金化程度越高。
The alloying behavior of the core-shell Ag-Au nanoparticles was modeled by molecular dynamics and improved analytic embedded atomic potential. The effect of shell thickness on the alloying properties of the alloy was analyzed from the aspects of atomic diffusion, microstructure evolution and alloying. The impact of the act of The results show that when the shell is thinner, the phenomenon of atomic diffusion at the core-shell interface is significant, the core exhibits a polyhedral morphology, and the surface Au and Ag atoms are completely mixed. When the shell is thick, the surface atoms mainly diffuse, and the whole particle surface is polyhedral, but the core keeps the original spherical structure. The morphology has been altered by the fault growth pattern. The thinner the shell, the higher the degree of alloying.