Structural evolution in nano-crystalline Cu synthesized by high energy ball milling

Nano-crystalline copper with a mean crystallite size of 27 nm was synthesized through solid state reduction of Cu2O by graphite using high energy planetary ball mill. The structural and morphological changes during mechanical milling were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mean crystallite size and residual strain were determined by XRD peak broadening using the Williamson–Hall approximation. It was found that the reaction is completed in a manner like a nucleation and growth process. Although the crystallite size and internal strain changes in Cu2O were regular during mechanical milling, there was an irregularity in both parameters in Cu particles. This irregularity was probably due to the progressive formation of copper during milling.