Study of a nanocrystalline cobalt coating prepared by area-selective electrodeposition.

Nanocrystalline Co coatings were successfully prepared on the surface of a steel substrate by droplet contact electrodeposition. Area-selective electrodeposition is performed by electrolyte drops contacting the surface of the substrate. By analyzing the current-time curve during the preparation of the coating, the influence of the selected area deposition pattern on the current-time curve is summarized. Meanwhile, microscopic observation, phase composition analysis, and performance testing of the coating were performed. The results show that the control procedure and deposition method directly affect the organization, morphology, and quality of the coating. The limited electrodeposition area and its continuous movement increase the nucleation rate and limit the growth of crystal nuclei. Therefore, the area-selective electrodeposition method has great advantages in preparing nanocrystals. The nanocrystalline Co coating was prepared on the surface of a steel substrate, and the surface hardness and corrosion resistance were improved.