Atomic scale insights into the first reaction stages prior to Al/CuO nanothermite ignition: influence of porosity - Équipe Nano-ingénierie et intégration des oxydes métalliques et de leurs interfaces Accéder directement au contenu
Article Dans Une Revue ACS Applied Materials & Interfaces Année : 2022

Atomic scale insights into the first reaction stages prior to Al/CuO nanothermite ignition: influence of porosity

Résumé

This theoretical work aims to understand the influence of nanopores at CuO-Al nanothermite interfaces on the initial stage of thermite reaction. ReaxFF molecular dynamics simulations were run to investigate the chemical and structural evolution of the reacting interface between the fuel, Al, and oxidizer, CuO, between 400 and 900 K and considering interfaces with, and without a pore. Results show that the initial alumina layer becomes enriched with Al and grows primarily into the Al metal at higher temperatures. The modification of alumina is driven by simultaneous Al and O migration between metallic Al and the native amorphous Al 2 O 3 layer. However, the presence of a pore affects significantly the growth kinetics and the composition of this alumina layer at temperatures exceeding 600 K, which impacts the initiation properties of the nanothermite. In the system without pore, where Al is in direct contact with CuO, a ternary aluminate layer, a mixture of Al, O and Cu, is formed at 800 K which slows Al and O diffusion, thus compromising the nanothermite reactivity in fully-dense Al/CuO composites. Conversely, the presence of a pore between Al and CuO promotes Alenrichment of the alumina layer above 600 K. At that temperature, any free oxygen molecules in the pore become attached to the reactive alumina surface resulting in a rapid oxygen pressure drop in the pore. This is expected to accelerate the reduction of the adjacent CuO as observed in experiments with Al/CuO composites with porosity at the CuO-Al interfaces.
Fichier principal
Vignette du fichier
paper-final_.pdf (1.97 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03695605 , version 1 (15-06-2022)

Identifiants

Citer

Hicham Jabraoui, Alain Esteve, Mirko Schoenitz, Edward L Dreizin, Carole Rossi. Atomic scale insights into the first reaction stages prior to Al/CuO nanothermite ignition: influence of porosity. ACS Applied Materials & Interfaces, 2022, 14 (25), pp.29451-29461. ⟨10.1021/acsami.2c07069⟩. ⟨hal-03695605⟩
39 Consultations
50 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More