Role of size effect and interface coarseness in energetic reactivity of Al/Cu nanoparticles

ER Wang and JH Jiang and Y Qiu and YH Chu and JP Zhang and HB Sun and YF Yan and YC Cui and YY Zhang, AIP ADVANCES, 15, 075033 (2025).

DOI: 10.1063/5.0269005

Using molecular dynamics simulation, we investigated the exothermic alloying procedure of Al/Cu nanoparticles with various sizes and interfacial contact areas. The results show that alloying reaction rates are determined by the diffusion barrier and contact area of initial configurations of Al/Cu nanoparticles. A higher interfacial diffusion barrier slows down the alloying rate of Al/Cu systems, while a larger interfacial contact area can accelerate the rate. During the alloying process, alloying reaction self-heating will occur slowly once an Al-Cu diffusion barrier is created at the interface, even though happening in the minimum size Al/Cu nanoparticle. Before the Al-Cu diffusion barrier layer appears at the interfaces, the melting of Al can make the alloying reaction more rapid. For the solid-state reaction of the Al/Cu interface, the larger interfacial contact area speeds up the alloying reaction of Al/Cu nanoparticles. The ignition temperature of Al/Cu nanoparticles is about 800 K, higher than our previous result (T ig = 700 K) of Al/Cu core-shell nanoparticles. It demonstrates that core- shell structure nanoparticles have a larger specific surface area and lower ignition temperature than the periodic nano-laminated structure.

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