Structural and magnetic properties of nanocrystalline NiFeCuMo powders produced by wet mechanical alloying

The NiFeCuMo nanocrystalline soft magnetic powders were successfully obtained by wet mechanical alloying route in a planetary ball mill using benzene (C₆H₆) as process control agent (PCA). The milling time used was ranging from 2 up to 20 h. The synthesis conditions and alloy formation have been investigated by X-ray and neutron diffraction as well as their influence on the intrinsic physical properties. Nanometer scale (≈10 nm) crystallites were obtained. A decrease of the samples magnetization has been observed and attributed to the stresses induced during the milling and to the benzene adsorbed on the powders surface. Differential scanning calorimetry investigation shows the presence of an exothermic peak related to the presence of benzene. The adsorbed benzene, internal stresses and crystalline defects removal took place during the heat treatment at 350 °C for 4 h, leading to an improvement of the powders magnetization.