A study of the ion treatment of rolled Л63 brass surface in a helicon discharge plasma flow in argon is conducted. It is found that argon ions with a high density provided by a helicon discharge not only intensively sputter the surface of brass, clean it of uncontrolled impurities, significantly increase the purity class of the brass surface, but also cause a significant modification of the surface. Depending on the ion etching time (10–45 min) and the current density (3.5–5.5 mA/cm$^{2}$), ordered highly oriented 3D ZnO nanostructures are formed on the brass surface. Nanocrystallites up to 70–90 nm are obtained in different modes. 3D ZnO nanostructures’ properties significantly depend on the processing modes. Synthesized ZnO nanocrystallites can play the role of transitional gradient layer during the further forming by physically vapour deposition protective coatings with high adhesive strength to the brass processed in the helicon discharge.