Microstructure and electrochemical corrosion behavior of Cr–Ni–Fe alloy deposits electroplated in the presence of trivalent Cr ions

• Cr–Ni–Fe alloy deposits were obtained in an eco-friendly Cr (III) bath.
• Cr–Ni–Fe alloy deposits with different Cr, Ni and Fe contents were achieved.
• Fe-rich and Cr-rich deposits were obtained by varying the plating current density.
• Fe-rich deposits are crystalline, but Cr-rich deposits are amorphous.
• An electrochemical corrosion test was conducted with Fe- and Cr-rich deposits.

Cr–Ni–Fe alloy deposits containing different Cr, Ni and Fe contents were created by varying the electroplating current density in an eco-friendly trivalent Cr-based bath with Ni2 + and Fe2 + ions. The Cr content of the Cr–Ni–Fe alloy deposits increased from 14 to 75 wt.% when the electroplating current density changed from 15 to 25 A/dm2. The mapping result obtained with a scanning electron microscope showed that a uniform ternary Cr–Ni–Fe alloy deposit could be obtained from the proposed bath, and X-ray diffraction results indicated the Fe-based alloy electroplated at 15 A/dm2 was crystalline, whereas the Cr-based alloy deposits electroplated at a high current density had an amorphous structure. The electrochemical corrosion test results showed that the corrosion resistance of the Cr–Ni–Fe alloy deposit electroplated at 20 A/dm2 was better than that of the Cr–Ni–Fe alloy deposit obtained at 25 A/dm2, despite having almost identical chemical compositions. These results were obtained by performing an electrochemical test and microstructure observations.