Effect of annealing in hydrogen on composition, structure and magnetic properties of rapidly quenched Fe-Co-Si-TM-B ribbons

In this paper we demonstrate that it is possible to extract boron from amor phous ribbons by annealing in dry hydrogen. This method is applied to Fe-Co -Si-TM-B ribbons (TM = Mn, Cr), leading to boron-free crystalline Fe-Co-Si- TM ribbons for compositions which are not accessible by traditional metallu rgy (casting, forging. rolling) because of their brittleness. The coercivit y of properly annealed ribbons ranges between 0.5 and 1A/cm. These values c ompare well to conventionally prepared Fe-Co alloys. The magnetisation ill a field of 15 kA/cm varies from more than 2 T to about 1.7 T for Fe-Co allo ys with addition of 3 wt% Si and 3 wt% of Mn or Cr. (C) 2000 Elsevier Scien ce B.V. All rights reserved.