Fabrication of Defect-Free Fe–Mn Alloys by Using Electrodeposition

Abstract

Nanocrystalline Fe–Mn alloys for molds with high strength, high thermal stability, and relatively low cost were prepared by electrodeposition. We used electrolytes that primarily consisted of iron sulfate and manganese sulfate combined with manganese chloride. Since electrodeposited Fe–Mn alloys tend to include many defects that greatly reduce their mechanical properties, we developed a method for reducing the number of defects in Fe–Mn alloys. The presence of surface cracks was strongly related to the orientation index for the (200) plane, which can be controlled by the amount of Mn. The number of voids was decreased as the current efficiency increased by controlling the current density and pH. An Fe–Mn alloy with no surface cracks was successfully fabricated by optimizing the current density and Mn/Fe molar ratio.