ELECTRODEPOSITION BEHAVIOR OF Mn WITH Ni IN ACIDIC SULFATE SOLUTIONS

Abstract

The influence of Mn 2+/ Ni 2+ mole ratio in electrolytes on the Ni – Mn alloy deposits was studied. The electrodeposition mechanism of Mn with Ni is analyzed by the cyclic voltammogram (CV) and an "induced co-deposition" mechanism is proposed for Ni – Mn alloy electrodeposition. The results show that the Mn content in Ni – Mn alloy deposit and the hardness increased with the increase of Mn 2+/ Ni 2+ mole ratio in electrolytes. When the Mn 2+/ Ni 2+ mole ratio in bath was 2/1, the corrosion current density of the deposit coating was the lowest and the corresponding corrosion potential was higher, and under these conditions the coating with a Mn content of 1.20 wt.% showed good corrosion resistance. The scanning electron microscopy (SEM) of the alloy coatings exhibited that the morphology of Ni – Mn alloy coatings were different from Pure Ni coating, and when Mn 2+/ Ni 2+ was 2/1, the surface was compact and homogeneous.