Magnetic properties of amorphous Fe-Cr-Si-B alloys

Substitution of Fe with Cr in amorphous (Fe1-xCrx)z(Si0.3B0.7)100-z( ) alloys was investigated. Cr decreases Curie temperature quite greatly, but it also slightly increases crystallization temperature. Cr improves soft magnetic properties, namely, it decreases coercive force and magnetic core loss, and increases initial magnetic permeability. An amorphous alloy, with (Fe0.925Cr0.075)83Si5B12composition, is obtained which has superior soft magnetic properties comparable to Permalloy or Ferrites: coercive force 0.024Oe, initial permeability at 1 kHz 12,000 and magnetic core loss at f = 20 kHz and B= 3 kG 140 mW/cm³. The above magnetic properties can be achieved by annealing at 400°C for 15 minutes without magnetic field.