In the present work, Ni-Al-Ta composite coatings were successfully fabricated on Al alloy substrate by mechanical milling technique. The microstructure, phase composition, tribological properties of coatings and the transfer of Al powder have been studied. It was found that the microhardness of the coatings were higher than the Al substrate, especially 10% and 15% Ta were added into the coating, and the composite coatings demonstrated excellent protective effect to the Al substrate. From the evolution of Al, Al3Ni, Al3Ni2, AlNi and Ni to conclude the content of Al element (at.%) is: composite coating > coarse particle (+80 mesh) > fine particle (-80 mesh). (C) 2018 Elsevier B.V. All rights reserved.