Post-supercritical CO2 electrodeposition approach for Ni-Cu alloy fabrication: An innovative eco-friendly strategy for high-performance corrosion resistance with durability

This work focuses on two meaningful points, one is the utilization of supercritical CO2 as a green solvent, and the other is achieving the proper distribution of Ni and copper Cu in the Ni-Cu alloy, as a protective layer to inhibit the corrosion. For the first time, a new post-supercritical carbon dioxide (PSC-CO2) mediated electrodeposition approach has been employed to prepare Ni-Cu alloy film. The use of SC-CO2 eliminates the need for hazardous surfactants. For the electrodeposition of Ni-Cu alloys, in the conventional method, Ni deposition predominates, whereas in the SC-CO2 method Cu deposition predominates. When combining both techniques, a proper proportion of Ni% and Cu% were achieved in Ni-Cu alloys. The physical characteristics were examined using spectroscopic techniques. The findings of electrochemical tests conducted in a 3.5% NaCl corrosive medium demonstrate that Ni-Cu alloy prepared using the PSC-CO2 approach has higher corrosion resistance than alloys prepared using the SC-CO2 and conventional methods. Moreover, it exhibits the enhanced charge transfer resistance (Rct = 1352 Ω) even after the 732 h continuous immersion in the corrosive medium. Therefore, the PSC-CO2 technique for producing Ni-Cu films can be an eco-friendly approach for superior corrosion resistance performance with long-term stability.