In this investigation The NiFe-CNT and Ni 3 Fe-CNT nanocomposites have been fabricated by high energy mechanical alloying method. X-ray diffraction analysis and scanning electron microscope have been employed respectively for following of formation process of alloys and morphological changes of the powder particles. Powder samples have been heat treated at 500 ?C for 1 h to release the milling induced stresses and lead to improved magnetic properties. Also bulk samples have been fabricated by sintering of powders at 1040 ?C for 1 h to study the mechanical properties. The magnetic properties of the samples have been derived from hystersis curve plotted by vibrating sample magnetometer procedure. Results showed that NiFe and Ni 3 Fe alloys have been obtained after 30 and 20 h of mechanical alloying, respectively. The microhardness values of these alloys have been measured 650 and 720 Vickers, respectively. Determining of curie temperature showed the presence of the second magnetic phase due to addition of CNTs to the matrices, although the XRD patterns of these samples didn't show any sign of the second phase. In the case of both alloys, the heat treatment led to increase of curie temperature and addition of CNTs caused to a decrease in curie temperature. The addition of CNTs to Ni 3 Fe alloy led to a decrease of saturation magnetization from 95 to 69 emu/g and an increase of coercivity from 16.5 to 78 Oe. Also, the value of saturation magnetization and coercivity increased respectively from 135 emu/g and 5.5 Oe for NiFe matrix to 140 emu/g and 31 Oe for FeNi-CNT. A little increase of saturation magnetization at FeNi-CNT than matrix alloy can be due to the presence of the second phase in the structure. The XRD patterns of the bulk samples detected the peaks of the nickel carbide phase and consequently proved the reaction between the nickel and carbon nanotubes at the sintering temperature. This is more clear in the case of Ni 3 Fe-CNT nanocomposite. However, presence of CNT reinforcements in the structure of bulk samples led to increase in relative density, hardne and improve of wear properties. Key Words: Nickel-iron alloys, Nanocomposite, Carbon naotube, Mechanical alloying, Magnetic materials
