The formation of ultrafine spherical metal powders using a low wettability strategy of solid–liquid interface

Highlights: • Spherical metal droplets were formed in graphite or graphene matrix with the help of interfacial and surface tension. • In the process of forming spherical metal particles, the heat treatment history and gas atmosphere can be controlled. • It provides an additional way for the formation of spherical metal powders. Here, we present a liquid–solid method (termed "LS method") for the formation of spherical metal powders. By taking advantage of the low wettability of metal liquids on a solid powder, spherical metal droplets were formed under the influence of interfacial and surface tension, as demonstrated for copper, silver, aluminum, copper–tin alloy, copper–zinc alloy, and amorphous magnetic iron–silicon–boron materials. This LS method is a versatile and universal route and would be applied in powder metallurgy, 3D printing and metal injection modeling. We believe this method provide an additional way for the formation of spherical metal powders.