Electrodeposition of Sn–Fe alloys using gluconate electrolytes and X-ray diffractometry and Mössbauer studies of the deposits

Abstract

Electrodeposits of tin–iron (Sn–Fe) are obtained from a gluconate based electrolyte using a constant current technique. The effects of plating parameters such as current density, deposition time, deposition temperature and pH were examined in relation to phase composition, structure and quality of deposit. The magnetic anisotropy of the alloy deposits was investigated mainly by 57Fe and 119Sn conversion electron Mössbauer spectroscopy (CEMS), transmission Mössbauer spectroscopy and X-ray diffractometry (XRD). 57Fe and 119Sn CEMS spectra and XRD show that the dominant phases of the deposits are tetragonal FeSn 2 or amorphous Fe–Sn. It was found that the relative area of the 2nd and 5th lines of the sextets representing the magnetic iron containing phases decreases with increasing current density. However no essential change in the magnetic anisotropy could be found with change of the plating time or temperature. The 119Sn spectra also revealed the presence of small amounts of β-Sn besides the main phases of the Sn–Fe binary deposits. It was concluded that a range of metallic good quality amorphous Sn–Fe alloys can be obtained using specific electrodeposition conditions consisting of a bath metal ratio of Sn:Fe of 1:3, 60 °C and a pH range of 5.0–7.0.