抄録
Spherical submicron-size copper powder was synthesized through condensation from a vapor phase with a significantly high degree of supersaturation in Ar-H2 plasma. The degree of supersaturation was increased by the relatively high rate feeding of raw copper powder of 40 micro m in size. The copper vapor concentration depended on the powder feed rate, reactor pressure and hydrogen flow rate. Relatively large particles of up to 0.1 micro m were prepared. Quench gas gave the formation of nanoparticles of 50nm in diameter even from a high concentration copper vapor. The quenching gas in the counter direction of the plasma flow restrain the particle growth due to increase of cooling rate. Also, Cu-W composite powders were synthesized through the Ar-H2 plasma treatment of mixture of Cu-WO3 powders. The starting temperature of shrinkage of Cu-20wt%W composite was significantly higher than pure Cu powders.
