Soft magnetic FeCo alloys: alloy development, processing, and properties

Abstract

FeCo intermetallic alloys are well known to possess a unique combination of high saturation magnetisation, high Curie temperature, low magnetocrystalline anisotropy and good strength. They are ideally suited for applications requiring high flux densities. Intense research and development efforts over the years resulted in significant improvements in mechanical properties and better understanding of phase transformations in FeCo alloys. However, the high cost of the alloys has prevented their widespread applications. Emerging needs for soft magnetic materials to operate at high temperatures have caused renewed interest in FeCo alloys. The earlier studies are summarised in this review with special emphasis on phase transformations, processing, mechanical, magnetic and electrical properties of binary, ternary and more complex FeCo alloys. Current interest in developing nanocrystalline and thin films based on FeCo compositions is also summarised. The research areas that need to be addressed are also emphasised to clearly elucidate the effects of alloying additions and processing on the electrical and magnetic properties and on the high temperature mechanical properties of these alloys.

Magnetic properties of cubic FeCo nanoparticles with anisotropic long chain structure

“…The coercivity of the well-dispersed sample S2 is large compared with bulk FeCo alloy whose coercivity is around 2 Oe. 23 The coercivity of S1 was much larger than that of S2. Hysteresis loop of S1 at 10 K as shown in figure 4 was very similar to the one at 300 K. At 10 K M r /M s ratio was 0.56 and 0.53 at 300 K, where M r is the remanent magnetization and M s is the saturation magnetization, and coercivity increased a little bit from 765 Oe to 810 Oe.…”

An inspection of force reduction in high force electromagnetic tweezers made of FeCo-V foil by laser cutting

“…13,16 FeCo alloys, which exhibit high M s , high Curie temperature, and low magnetocrystalline anisotropy, are ideally suited for applications requiring high flux density. 17 Although binary FeCo alloys have the highest saturation magnetization, they are limited to use in many applications on account of their brittleness. With the addition of vanadium as in industrial production, the workability of these alloys can be improved without decreasing the magnetization too much.…”

Thermodynamic properties of dilute Co-Fe solid solutions studied by 57Fe Mössbauer spectroscopy

“…As a result of all of the above Co-Fe alloys are attractive materials for many applications, even at elevated temperatures. In particular, these alloys are used in the production of turbine engine components, transformers, magnetic bearings and recording heads [1][2][3][4][5]. At the same time, this system is regarded as a model for experimental and theoretical studies of thermodynamic properties [6][7][8].…”