Synthesis of WMoTaNb nanopowders by molten salt-assisted magnesiothermic reduction

A novel synthetic approach is reported for producing WMoTaNb refractory high-entropy alloy nanopowders via a combination of chemical co-precipitation, calcination, and molten salt-assisted magnesiothermic reduction. The formation of (W,Mo,Ta,Nb)O_x composite nanopowders enabled in-situ synthesis of WMoTaNb through enhanced interfacial reactivity and shortened atomic diffusion pathways. Subsequent molten salt-assisted magnesiothermic reduction under continuous heating facilitated synergistic enhancement of magnesium-mediated atomic diffusion, thereby enabling the formation of a uniform WMoTaNb high-entropy phase. The as-synthesized nanopowders exhibited a narrow size distribution, with the majority of particles measuring below 60 nm in diameter. This methodology demonstrates the effectiveness of integrating reactive oxide precursors and molten salt chemistry to achieve controlled synthesis of refractory high-entropy alloys at the nanoscale.