Effect of Cobalt on the Nano-Mechanical and Magnetic Properties of Electroformed Fe–Ni–Co Thin Film

Abstract

Fe–Ni–Co thin film less than 15 μm thick was electroformed in a modified sulfate bath to study the effect of cobalt (Co) on the nano-mechanical and magnetic properties. The cobalt content of the Fe–Ni–Co film depends on the content of Co2+ ions in the bath. As the cobalt content increases in the Fe–Ni–Co film, initial α-[Fe, Ni] (Im-3m) became γ-[Fe, Ni] (Fm-3m) with precipitates of Co3Fe7 (Pm3m) phase. Average grain sizes of the Fe–27%Ni, Fe–22%Ni–2%Co and Fe–22%Ni–8%Co thin sheet with same plating time of 10 min were similar values of about 2.64 (nm) in error range. Their nano-hardness, stiffness and fatigue limit determined by Alekhin model were 4.7, 5.4, 5.8 (GPa), 1.1, 1.4, 1.7 (GPa), and 0.027, 0.029, 0.032, respectively. The maximum magnetization, coercive force and susceptibility were 196, 178, 148 (emu/g), 8.5, 21.9, 29.6 (Oe), 0.3067, 0.3018, 0.2120 (H/m), respectively.