The microstructure and magnetic properties of FeCo alloys with different OH over bar /(Co2+, Fe2+) ratio and annealing temperature

The OH over bar /(Co2+, Fe2+) ratio and annealing temperature (T-a) have a great influence on the microstructure and magnetic properties of FeCo alloys. In this work, the OH over bar /(Co2+, Fe2+) ratio was first changed from 10:1 to 30:1. When the OH over bar /(Co2+, Fe2+) ratio was 20:1, pure FeCo powder samples were obtained. After annealing at 400 degrees C, the saturation magnetization (M-s), remnant magnetization (M-r), and coercivity (H-c) were 155 emu/g, 15 emu/g, and 210 Oe, respectively. Then the prepared FeCo samples were annealed in the range of 300 degrees C-600 degrees C for 5 h. With the increasing of T-a, the better magnetic properties of FeCo powders were observed. When the T-a was 600 degrees C, the M-s, M-r, and H-c were 202 emu/g, 12 emu/g, and 87 Oe, respectively. When the OH over bar /(Co2+, Fe2+) = 20:1 and T-a was 400 degrees C, the real part of complex permittivity was between 8.2 and 9.5, and the corresponding imaginary part was between - 0.3 and 1.3. Furthermore, the maximum reflection loss (RL) value of FeCo powders (20-30 nm) was - 35.49 dB which showed great potential in corresponding industrial applications.