Abstract: The copper powder was ball-milled in HCl solution (pH=2) by high-energy ball milling. Both milling balls and container were made of pure copper. The weight ratio of Cu balls with in diameter of 15mm to the weight of powder was 20:1, and all milling was carried out at a speed of 300r/min. The pure copper powder was transformed to Cu₂O fundmentally after 3h ball milling while the pure Cu₂O with the diameter of 50--100nm was obtained after 70h ball milling. The as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The mechanism of the formation of Cu2O and the effect of milling parameters on the formation of Cu2O were discussed.

Key words: mechanochemistry, Cu₂O nanoparticle, high-energy ball milling