Nanoparticles produced by nanosecond pulse laser ablation of a metallic glass in water

Abstract In this paper, we perform a single nanosecond pulse laser ablation of a Zr-based metallic glass (Vitreloy 1) target in water. The violent ejection of high-temperature ablation matter is observed from the target by means of explosive boiling, which is accompanied by a formation of cavitation bubble. These ablation products entered the water include a rich variety of nanoparticles that can be classified into three different types: full amorphous, amorphous-crystalline composite, and polycrystalline. The amorphous nanoparticles have relatively smaller sizes and a uniform elemental distribution. The latter two types of nanoparticles exhibit a unique core-shell feature with an obvious compositional segregation. It is proposed that the diversity of the nanoparticles closely depends on the different pathways that they enter the water: directly before the bubble formation or via the bubble, in which the cooling rate and the glass-forming ability of ablation products are two competing factors.