The mechanism of hydrogen reduction synthesis of nanocomposite W-Cu powders

The formation mechanism of nanocomposite W-Cu powder during reduction of ball milled W-Cu oxide mixture was investigated by analyses of powder characteristics and phase decomposition. The synthesis of nanosized tungsten powders is possible if P-H2O/P-H2 and fetal surface area of reaction zone are optimized to promote nucleation process and to suppress the growth of tungsten particles. The experimental result showed that the BM powder might provide an optimum condition for the formation of nanosized tungsten powder by fulfilling the above requirements. In addition, the pre-reduced Cu phase in the aggregates is thought to contribute to the formation of nanoscale W particles by lowering the contact frequency of the W phase or the W oxide phase. (C) 1997 Acta Metallurgica Inc.