A Nanograins-attached and Ultrathin Cu Flake Powder Fabricated by High Energy Mechanical Milling and Dealloying

Abstract Metal powders with hierarchical nanostructures are generally designed and fabricated by dealloying with or without assistance of other processes. However, they are mainly nanoporous metal powders and their derivatives which have limited applications, so metal powders with novel nanostructures should be explored further for various applications. Herein, high energy mechanical milling and dealloying were combined for fabricating metal powders with controllable nanostructures. As an example, a nanograins-attached and ultrathin Cu flake powder was fabricated by partial mechanical alloying of a Cu-42wt.%Al powder mixture and subsequent dealloying. The dealloyed Cu powder particles had ultrathin flaky shapes with numerous Cu nanograins being attached to their surfaces, and the microstructure of the as-milled Cu-42wt.%Al powder particles and the dealloyed Cu particles were studied to elucidate the formation mechanism of the unique morphology of the dealloyed Cu powder.