Grain Diameter and Magnetic Properties of Rapidly Quenched Fe-M-Si-Ge (M=Ti, V, Zr, Nb, Ta) and Fe-Hf-Cu Alloys

The grain diameters and magnetic properties of rapidly quenched Fe-M-Si-Ge (M=Ti, V, Zr, Nb, Ta) and Fe-Hf-Cu alloy ribbons were investigated. The grain size of Fe-Ta-Si-Ge alloys decreases rapidly from 2700 A to about 400 Å with the addition of up to 3 at% Ta. The coercivity increases rapidly from 2.3 to 30 Oe with increasing Ta content. For the Fe-M-Si-Ge alloy systems, the decrease in grain diameter and increase in coercivity with the addition of M rank in the order Ta, Nb, Zr, Ti, V. The grain diameter of Fe-Hf-Cu alloys decreases to about 600 Å as the Hf content is increased to 4 to 6 at %. The coercivity increases to about 20 Oe with increasing Hf content. The coercivity of these rapidly quenched Fe-base alloys is roughly proportional to the reciprocal of the grain diameter.