Microstructures and Soft Magnetic Properties of Fe(73.5−x)Cu(1)Nb(3)Si(13.5)B(9)Gd(x) (x = 0–1.5) Alloys

In this experiment, the rare earth Gd element was added to Finemet alloy to observe the microstructure and soft magnetic properties. The experimental results showed that the samples with the addition of 0.5% Gd and 1.0% Gd can be quenched and cast normally, and the M(S) of Fe(73)Cu(1)Nb(3)Si(13.5)B(9)Gd(0.5) alloy was 10.41% higher than that of Finemet. After annealing, crystal grains of about 10 nm were formed. The μ(i) and μ(m) values of Fe(73)Cu(1)Nb(3)Si(13.5)B(9)Gd(0.5) alloy were 25.51% and 22.23% higher, respectively, and the coercivity H(C) was reduced by 12.19% compared to Finemet. At 1 kHz, the μ(e) value of Fe(73)Cu(1)Nb(3)Si(13.5)B(9)Gd(0.5) alloy at room temperature was 14.57% higher than that of Finemet, while the μ(e) reached 162.34 k and 142.42 k at 90 °C and 150 °C (24% and 29.51% higher, respectively). The Fe(72.5)Cu(1)Nb(3)Si(13.5)B(9)Gd(1.0) alloy had the best performance at 100 kHz, with higher μ(e) values than Finemet across the ambient temperature range of 30 °C to 150 °C. After tension annealing, the μ(e) values of Fe(72.5)Cu(1)Nb(3)Si(13.5)B(9)Gd(1.0) alloy were 20–30% higher than those of Finemet.