Enormously high rate of evaporation from liquid pure copper was found when
NH3 gas was top-blown. Smoke of fine spherical particles of Cu was observed
by laser light sheet method. Nitrogen in the melt was supersaturated during
NH3 gas blowing. The formation of an unstable and volatile copper compound
such as CuNx or CuH was suggested in addition to the cooling effect due to
endothermal decomposition of NH3.