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

摘要

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 Ni~(2+) and Fe~(2+) 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/dm~2. 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/dm~2 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/dm~2 was better than that of the Cr-Ni-Fe alloy deposit obtained at 25 A/dm~2, despite having almost identical chemical compositions. These results were obtained by performing an electrochemical test and microstructure observations.