Hysteresis and Loss Measurements on the Plastically Deformed Fe–(3 wt%)Si Under Sinusoidal and Triangular External Field

The effect of different degrees of plastic deformation on the frequency dependence of coercive field and losses in NO Fe-(3 wt%)Si was investigated measuring hysteresis loops on a ring-shaped core over a frequency range of 0.5-1000 Hz. The investigation was performed under sinusoidal and triangular external field H(t). Although H(t) induce a similar quasi-sinusoidal magnetic induction (similar hysteresis loops), the loop area is smaller for that measured by triangular applied field resulting in smaller magnetic losses. The coercive field and the total losses of all samples increase with increasing frequency; however, the influence of frequency becomes gradually smaller with plastic deformation. The total losses that increase due to plastic deformation at low frequencies become at high frequencies smaller in deformed samples than in an undeformed material. A similar behavior was found in the frequency dependence of the coercivity. Due to a periodic quasi-sinusoidal B(t), the losses were analyzed using the concept of loss separation. While the quasi-static (hysteresis) loss increases, classical and excess losses decrease with increasing deformation.