Effect of electrolysis conditions on the formation, structure, and magnetic properties of a finely divided iron-cobalt alloy

Abstract

An investigation was carried out into the effect of electrolyte concentration and current density on current efficiency in the electrodeposition of Fe, Co, and Fe-Co alloy powders. It was established that raising the electrolyte concentration from 6.65 to 26.62 g/liter of Fe2+ + Co2+ increases current efficiency, whose maximum value is about 90%. The highest current efficiency is attained at ic of 20–30 A/dm2. Changing the electrolyte concentration and current density does not significantly affect the composition of alloy deposits. At an iron-to-cobalt ion content ratio in the electrolyte of 1∶1 the rate of discharge of Fe2+ during alloy formation in the twolayer bath is greater than that of Co2+. X-ray structural analysis revealed that the greatest changes in the internal structure of a very finely divided iron-cobalt alloy take place at low electrolyte concentrations. That raising the electrolyte concentration facilitates alloy formation is confirmed by a decrease in the degree of defectiveness of the particles and a stabilization of the crystal lattice parameter of the alloy; ic does not have such an effect on the structure of the alloy. Magnetometric measurements demonstrated that the coercive force of alloy powders is greater at higher densities of dislocations in their particles.