Tartrate-Based Electrolyte for Electrodeposition of Fe–Sn Alloys

Magnetic properties of the sustainable Fe−Sn alloys are already known. However, there is lack of information in the field of Fe−Sn electrodeposition. In the present study, a novel Fe(III)−Sn(II) electrolyte with tartaric acid as a single complexing agent is introduced. The influence of the pH and the current density on the structural properties of the Fe−Sn deposit was studied. The stability of the electrolytes as a main attribute of sustainability was tested. The ferromagnetic phases Fe5Sn3 and Fe3Sn were electrodeposited for the first time, and it was found that the mechanism of the Fe−Sn deposition changes from normal to anomalous at a pH value 3.0 and a current density of approximately 30 mA/cm2. A possible reason for the anomalous deposition of Fe−Sn is the formation of Fe-hydroxides on the cathode surface. Two electrolyte stability windows exist: The first stability window is around a pH value of 1.8 where bimetallic Fe−Sn tartrate complexes were formed, and second one is around a pH value of 3.5 where most of the Sn ions were present in the form of [Sn(tart)2]2− and Fe in the form of [Fe(tart)]+ complexes