Structural and Magnetic Properties of Ni 45 Al 45 C 10 Nanocrystalline Alloys

The magnetic properties and structure of Ni 45 Al 45 C 10 nanocrystalline alloys prepared by the mechanical alloying process are studied as a function of milling time. The milling times are 1, 2, 4, 6, and 12 h. The effect of milling time on structural characterization was investigated by an X-ray diffractometer (XRD) and extended X-ray absorption fine structure spectroscopy (EXAFS). Both XRD and EXAFS studies showed that the alloying process occurred after 4-h milling. The nano particle size and shape are examined by scanning electron microscopy. Magnetic properties are examined by vibrating sample magnetometer. Magnetic saturation is decreased with milling time, which seemed be due to substitution of Ni atoms by Al or C atoms resulting in magnetic dilution and/or decreasing of particle size. The coercivity (Hc) is decreased with milling time indicating the increase in single-domain size owing to the crystallite size reduction.