Flowability of Electrolytic Copper Powder

The surface structure of powder particles, which allows free flow of copper powder, was examined. It has been shown that a sufficiently dense surface structure which permits free flow will be obtained if apparent density is higher than 2.2 – 2.3 g/cm3. Such a surface structure can be obtained by reversing current electrodeposition of powder at considerably lower apparent densities of powder due to selective dissolution of subparticles during anodic time of reversing current wave. The surface structure of copper powder particles is discussed and correlated with the lowest apparent density at which the copper powder can still flow.