The thermodynamic origin for the structural transition pathway in metal oxide nanoparticles under acoustic shock excitation states

Abstract

The nature of the phase transition pathways in solids under acoustic shock conditions is largely unknown. Herein, we critically examine the results of the structural transition of 17 metal oxide nanoparticles, which include AX, AX2, A2X3 and A3X4-type oxides under similar shocked conditions. Post shock, most of the oxides exhibit stable crystal structures, while some demonstrate temperature-driven pathways, and few follow pressure-driven transitions. In consolidating, two key factors of thermal conductivity-dependent molten pool nucleation gap and cation chemoselectivity have been arrived at to determine the nature of the transition types. The proposed interpretation may bring about new structural transition concepts under extreme conditions.