Microstructural Control of Metal Sulfide Powder via Shock Wave Method

Abstract

This study aims to develop functional metal sulfide materials with nanoscale crystalline grain structures using a shock solidification technology based on cylindrical compaction with explosives. Compared with metals and ceramics, which have traditionally been the subject of explosive shock solidification, metal sulfides are characterized by their brittleness and low melting points. In this study, the slowest detonation velocity explosive, PAVEX, was used. The expansion of the explosive gas was employed to drive a metal tube at high velocity, causing it to impact a sample container at high speed, thereby generating shock waves utilized for powder compaction. In the case of Ni fine powder, densification and particle refinement were achieved under a shock pressure of approximately 19 GPa, resulting in significantly increased hardness. On the other hand, for CuFeS₂ fine powder, decomposition reactions occurred under pressures of around 9.8 GPa, and the desired microstructure control was not achieved. However, the formation of a high-pressure phase, cubanite CuFe₂S₃, was confirmed. These findings suggest the potential for novel phase synthesis in metal sulfides, and indicate promising prospects for future applications.

Graphical Abstract

Experimental assembly for explosive compaction.