Corrosion behavior and microstructure of electrodeposited nano-layered Ni–Cr coatings

• Ni–Cr electroplating has been conducted in a dimethylformamide (DMF)-mixed bath.
• Crack-free features of as-prepared Ni–Cr coatings have been confirmed.
• The Ni–Cr coatings show high anti-corrosion ability based on crack-free integrity.
• The dominated function of DMF during Cr electroplating has been illustrated.
• Good controllability for Ni–Cr coatings in nano- & microscales can be realized.

A successful electroplating process has been developed to make crack-free Ni–Cr coatings. A single bath with a mixed solvent of dimethylformamide (DMF) and water into which a low toxic solute of Cr(III) and Ni(II) salts is dissolved serves for the electroplating operation. Electrochemical measurements presented here offer new insights into the predominant function of DMF in promoting high quality and crack-free formation of Ni–Cr coatings. Representative images of crack-free Ni–Cr multilayer coatings in both nanometer and micrometer scales illustrate the ability to control thickness and composition of the coatings simply through adjusting current density and deposition time in the DMF-mixed bath.