Fabrication of equiatomic FeCo alloy parts with high magnetic properties by fields activated sintering

Abstract

Electrical field activated sintering technology combined with micro-forming (Micro-FAST), as a new rapid powder sintering/forming method, is used to fabricate FeCo alloy parts. The successfully prepared FeCo parts have a high saturation of 214.11 emu/g and a low coercivity of 16 Oe, and these values are 20% and 10% higher than that of commercially available FeCoV alloy parts on the saturation and coercivity respectively. During the sintering process, the high current application shortened the densification time and enhanced the uniformity of the microstructure significantly. The grain sizes of FeCo alloys were in a range of 5–6 µm, and good isotropy was also shown. The low angle grain boundary (LAGB) accounted for more than 30% and the low angle misorientation accounted for more than 30% of the sample parts. Furthermore, the formation of the nano B2 phase was promoted during the Micro-FAST, and the size of the B2 phase was about 5 nm. The coherent interface between α and B2 was conducive for reducing the coercivity. As a consequence, the outstanding microstructure formed by Micro-FAST makes the FeCo alloys have high saturation and low coercivity.

the influence of material electromagnetic properties to the electric motor performance

“…They consist of hysteresis and eddy current losses (1). The former depend on the material properties, reflected in the surface area of B-H hysteresis (Figure 1a), and frequency (2), while the latter depend on electrical conductivity, thickness, magnetic flux density and frequency (3). Assuming that the materials are rolled into sheets with the thickness of 0.35 mm, the calculated values for FeSi and FeCo specific losses are given in Table 2, where they are compared with the values of the reference materials, i.e.…”

“…In comparison to standard silicon steels (FeSi), which are commonly used for building the magnetic cores in the electric motor manufacutring, iron-cobalt (FeCo) alloys offer significant performance improvement due to lower magnetic field strength H, needed to magnetize the material, and higher saturation flux density Bsat values, which is reflected in more compact geometry, higher energy efficiency and mechanical power [1][2][3][4][5].…”