Preparation and characterisation of electrodeposited amorphous Sn–Co–Fe ternary alloys

Abstract

Electrochemical deposition was investigated as a process to obtain alloys of Sn–Co–Fe, which to date have not been reported in the literature. A constant current technique was used to electrochemically deposit tin–cobalt–iron alloys from a gluconate electrolyte. The gluconate system was chosen as an electrolyte, which could potentially provide an environmentally safe process. The effect of plating parameters such as current density, deposition time, temperature and pH are discussed. Results are reported for current density and plating time using an electrolyte temperature of 20–60 °C and pH of 7.0 in relation to phase composition, crystal structure and magnetic anisotropy of the deposited alloys. Investigations were conducted using 57Fe conversion electron Mössbauer spectroscopy (CEMS), 119Sn CEMS, transmission Mössbauer Spectroscopy and XRD. The 57Fe and 119Sn CEMS spectra and XRD showed that the dominant phase in the deposits was amorphous Sn–Co–Fe. The relative area of the 2nd and 5th lines of the sextets representing the magnetic iron containing phases was found to decrease continuously with increasing current density while at the same time no significant changes in the magnetic anisotropy was found with plating time. Magnetically split 119Sn spectra reflecting a transferred hyperfine field were also observed. A range of good quality amorphous Sn–Co–Fe ternary alloys was obtained over a range of operating conditions from an environmentally acceptable gluconate electrolyte.