Abstract: Nanophase CuO powders were made from Cu(NO₃)₂ by the complexing-precipitate method, and the effects of complexing agent on particle sizes studied. The results show that CuO powders are smaller in size and slightly aggregate. The sample particles thus obtained are spherical and their average particle sizes are between 40～60nm. With NH₃·H₂O as the complexing agent, the best reaction conditions for preparing nanophase CuO are that the reaction temperature is 30℃ and the molar ratio of Cu(NO₃)₂ to NaOH is 1:3.

Key words: complexing-precipitate, nanophase powder, cupric oxide