Iman Farahbakhsh - Shirvan Center, University of Applied Science and Technology, Shirvan, Iran
Nastaran Farahbakhsh - Department of Engineering, Nanomaterial Group, Tarbiat Modares University, Tehran, Iran

In this study, nanocrystalline Fe50Ni50 alloy powders were synthesized by Mechanical alloying process using planetary high- energy ball mill (Pulverisette 5, Fritsch) for milling times: 2,5,10,30,50,70 h and for the weight ratio of balls to powder (BPR) 30:1, under argon atmosphere. The alloy formation and different physical properties were studied as a function of milling time, using X-ray diffraction (XRD) technique, Field emission scanning electron microscopy (FESEM) Transmission Electron Microscopy (TEM), vibration sample magnetometer (VSM) and Fourier transform infrared (FTIR) spectroscopy. Increase in milling time, led to reduction in crystallite size (D) in the superparamagnetic phase, thus inducing a higher magnetization to the about 120 emu/g, which is significantly higher compared with the work of others. Also reduction in crystallite size led to lower coercivity. Optical studies showed that determined grain size based on hysteresis curve for 70h of milling time is in the same order of radiation wavelength

Nanostructure; Structure and Physical properties; superparamagnetic phase; FeNi; Mechanical alloying