Effect of carbon content on structure and magnetic properties for (Fe, Ni)1−xCx by mechanical alloying

FCC (Fe55Ni45)1−xCx supersaturated solid solution was prepared in a wide concentration range (0⩽x⩽0.9) by mechanical alloying of nanocrystalline Fe55Ni45 with graphite. The lattice constant of Fe55Ni45 increases linearly with increasing carbon content up to x=0.25. At the same time, it is found that the magnetic moment per metal atom (Fe, Ni) decreases linearly with increasing carbon content for 0⩽x⩽0.25 with a slope of 1.2 μB/at. For high carbon content, x⩾0.5, it is observed that the decrease of lattice constant and increase of moment per metal atom (Fe, Ni) with increasing C content, indicates that the dissolution of carbon is hindered by the high-volume fraction of graphite in the initial powder mixture. The complete amorphization of x=0.5 does not occur after the extended ball milling. The alloying effect of carbon on the magnetization is compared with other metalloid B, P, and Si in Fe- and Ni-based binary system.