Elaboration, Microstructure, and Magnetic Properties of Nanocrystalline Fe90Ni10 Powders

Nanocrystalline Fe90Ni10 alloys were synthesized by mechanical alloying, starting from a powder mixture of elemental Fe and Ni. The phase evolution and magnetic properties were investigated, as a function of milling time, using the X-ray diffraction (XRD), the vibrating sample magnetometer (VSM), and the 57Fe Mossbauer spectroscopy. From XRD results, we concluded the formation, after 13 h of milling, of a disordered phase α-Fe(Ni) (bcc). It has been shown that the increase of milling time decreases the crystallites size and increases the microstrains and the lattice parameter. When the crystallites size decreases, the coercive field, Hc, decreases first, then increases and finally reaches a constant value of about 26 Oe. During the periode of the alloy formation, the saturation magnetization, Ms, increases with decreasing crystallite size and reaches the highest value of 212 emu/g after 27 h of milling, then, Ms remains constant up to 48 h of milling. The adjustment of Mossbauer spectra revealed that the fraction of the (bcc) α-Fe(Ni) phase increased with milling time. After 13 h of milling, only the (bcc) α-Fe(Ni) phase is observed.