Preparation of spheroidized W−Cu pseudo-alloy micropowder with sub-micrometer particle structure using plasma technology

The possibility to obtain composite micropowders of the W−Cu system with spherical particles having sub-microscale/nanoscale internal structure was confirmed and studied using the complex multistage approach. Composite W−Cu nanoparticles with core–shell structure (W cores and Cu shells) were produced in plasmochemical synthesis in the first stage. Further spray-drying of the aqueous suspension of the W−Cu nanopowder with sucrose enabled the formation of 25−63 μm microgranules with a yield of 50%. The last step was the treatment of the nanopowder microgranules by a thermal plasma jet, which ensured the production of dense spherical W−Cu particles. The final powder had a spheroidization degree of 90%−95%, a bulk density of up to 8.1 g/cm3 and a flowability of 12 s/50 g. The contents of impurities in the resulting spherical micropowder were 0.7 wt.% O, 0.02−0.2 wt.% C and 0.03−0.05 wt.% H.