Structure and magnetic properties of mechanically alloyed nanocrystalline Fe-46 at.% Co-34 at.% Ni-20 at.% alloy powder from cryogenic to elevated temperatures

摘要

Nanocrystalline Fe46Co34Ni20 alloy powder was successfully fabricated by mechanical alloying. The alloy powder (mean particle size5.4m and grain size15nm) was composed of two phasesthe f.c.c. phase and the b.c.c. phase. At 300K, the saturation magnetization (M-S), the remanent magnetization (M-R), and the intrinsic coercivity (H-CI) of the as-fabricated alloy powder were 169Am(2)kg(-1), 2Am(2)kg(-1), and 3.3kAm(-1), respectively. The nanocrystalline powder exhibited significantly superior soft-magnetic propertiesdecrease in H-CI by 15 times and increase in M-S by 30%compared to the nanoparticles of similar compositions synthesized by chemical methods. The M-S, M-R, and H-CI decreased with an increase in temperature from cryogenic temperatures to ambient temperatures. The alloy powder was relatively stable up to 600K. The alloy powders thermally treated at 800K and 900K exhibited improved soft-magnetic properties compared to the as-fabricated alloy powderthe M-S increased by 12% and the H-CI decreased by 30%.