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.

The conditions for electrodeposition of Fe-Sn alloys from a novel, environmentally friendly, ferrous chloride-based electrolyte were studied. The influence of the pH on the electrolyte stability and deposit stoichiometry was discussed. Anodic stripping voltammetry (ASV), XRD and SEM/EDX were used to characterize the electrodeposited phases. The results from ASVs indicated the possibility to deposit at least two different phases at high overpotentials. Hull cell depositions in an electrolyte with a Sn to Fe ratio 1:1 and a pH value of 2.8 showed regular deposition of Fe-Sn. Fe-rich deposits (54.84 at %) were obtained from an electrolyte with Sn to Fe ratio 1:10. The XRD results were compatible with the electrochemical investigations. In all studied samples β-Sn, FeSn2 and Fe5Sn3 were detected. The presence of ferromagnetic Fe5Sn3 was not influenced by the Sn to Fe ions ratio in the electrolyte.