Structure, Mössbauer and magnetic studies of nanostructured Fe₈₀Ni₂₀ alloy elaborated by mechanical milling

Abstract

Nanocrystalline Fe₈₀Ni₂₀ alloy samples were prepared by the mechanical alloying process using a high-energy planetary ball mill. The formation and physical properties of the alloys were investigated as a function of the milling time, t, (in the range 0–48 h) by means of X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray, Mössbauer spectroscopy and vibrating sample magnetometer measurements. The complete formation of bcc FeNi was observed after 8 h milling. As the milling time increases from 0 to 48 h, the lattice parameter increases towards the Fe₈₀Ni₂₀ bulk value, whereas the grain size decreases from 69 to 11 nm. The powder particle morphology at different stages of formation was observed by SEM. The saturation magnetization and the coercive field derived from the hysteresis curves are discussed as a function of milling time.

Keywords:

• FeNi alloy
• nanostructured powders
• X-ray diffraction
• microscopy
• Mössbauer effect
• magnetic measurements