Study of the NaF-ScF3 system as a molten bath for production of Sc alloys: A combination of NMR and molecular dynamics simulations

Aydar Rakhmatullin (1, 2) , Kelly Machado (1, 2) , Didier Zanghi (1, 2) , Ilya Polovov (3) , Rinat Bakirov (4) , Konstantin Maksimtsev (3) , Catherine Bessada (1, 2)

1 CEMHTI - Conditions Extrêmes et Matériaux : Haute Température et Irradiation
2 UO - Université d'Orléans
3 UrFU - Ural Federal University [Ekaterinburg]
4 Izhevsk State Technical University

In situ high temperature NMR spectroscopy was used to characterize the NaF-ScF3 melt over a wide range of compositions. 19 F, 23 Na, and 45 Sc NMR spectra were acquired in NaF-ScF3 melts of up to 70 mol% of ScF3. The interpretation of all experimental results obtained in situ in the melt is significantly enhanced by the contribution of Molecular Dynamics (MD) calculations. A new interatomic potential for the molten NaF-ScF3 system was developed by using a Polarizable Ion Model (PIM). The potential parameters were obtained by force-fitting to density functional theory (DFT) reference data. MD simulations were combined with further DFT calculations to determine NMR chemical shifts for 19 F, 23 Na, and 45 Sc. The agreement between the experimental NMR data and the corresponding calculated data from our applied computational protocol indicated the polymerization and network formation in the melt. Additionally, the density and the electrical conductivity in the molten state were calculated from the statistical analysis of ionic trajectories obtained through MD simulations.

Mots clés: High temperature NMR; scandium fluorides; molten salts; Molecular Dynamics; DFT 1

Domaines: Matériaux

Aydar Rakhmatullin, Kelly Machado, Didier Zanghi, Ilya Polovov, Rinat Bakirov, et al.. Study of the NaF-ScF3 system as a molten bath for production of Sc alloys: A combination of NMR and molecular dynamics simulations. Journal of Alloys and Compounds, 2019, 786, pp.953-959. ⟨10.1016/j.jallcom.2019.02.057⟩. ⟨hal-02108670⟩