High B_s nanocrystalline alloys with high amorphous-forming ability

摘要

The soft magnetic property and the structure of the new type nanocrystalline Fe-(P,B,Si,Nb,Cu) alloy with high Fe content about 80 at. % have been investigated. In this paper Fe_(77.9)P_3B_(14)Nb_5Cu_(0.1) alloy has a supercooled liquid region (ΔT_x) of 33 K defined by the difference between the glass transition temperature (T_g) and crystallization temperature (T_x), which would be relating to the high glass-forming ability leading a thickness of 140 μm melt-spun ribbon with a glassy phase. The Fe_(80.9)P_2B_(10)Si_2Nb_5Cu_(0.1) alloy with the higher Fe content can be melt spun into the thick ribbon with thickness of 65 μm due to rather large amorphous-forming ability. In addition, a homogeneous nanostructure composed of α-Fe grain with around 15 nm in diameter was realized after crystallization, and the nanostructured alloy exhibits the high B_s of 1.55 T and the low coercivity (H_c) of 4.6 A/m. The B_s and the glass or amorphous-forming ability of the alloys are superior to those for typical nanocrystalline. Therefore, the miniaturization and the realization of higher efficiency of power supply circuits in electric devices are able to be expected using these nanocrystalline Fe-(P,B,Si,Nb,Cu) alloys.