Characterization of Ni-Co coatings fabricated by electrochemical additive manufacturing

Abstract

This study explores the influence of printing potential on the microstructure and corrosion behavior of Ni–Co coatings produced by electrochemical additive manufacturing (ECAM) at different applied potentials. The microstructure, chemical composition and phase of as-printed coatings were determined by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, respectively. The results showed that high voltage increased deposition rate and grain refinement, while shifting the preferred orientation from (111) to (220) crystal plane. The printed coatings exhibited a dual-phase FCC + HCP structure, consistent with anomalous co-deposition behavior. The Ni_24.7Co_75.3 coating printed at the potential of 2.5 V had the best corrosion resistance, showing the lowest corrosion current density of 23.93 μA/cm², the lowest corrosion rate of 1.04 mm/year, and a compact, smooth morphology with minimal defects. These findings demonstrate that low deposition voltage favors both structural integrity and corrosion performance, providing useful guidance for the development of corrosion-resistant alloy coatings in ECAM applications.