Process for producing a magnetic core of nanocrystalline soft magnetic material

摘要

Production of a magnetic core of soft magnetic iron-based alloy having a nanocrystalline structure involves determining the annealing temperature (Tm) required, for an amorphous ribbon of the alloy, to achieve maximum magnetic permeability and subjecting a core blank, produced from an amorphous ribbon of the alloy, to annealing at 20 - 50 (preferably 20 - 40) degrees C above Tm for 0.1 - 10 (preferably 0.5 - 5) hrs. to cause nanocrystal formation. The alloy has the composition (in atomic %) >= 60% Fe, 0.1 - 3 % (preferably 0.5 - 1.5) Cu, 0 - 25 % B, 0 - 30 % (preferably 12 - 17) Si, 0.1 - 30 % (preferably 2 - 5) one or more of Nb, W, Ta, Zr, Hf, Ti and Mo, and balance impurities, the sum of Si and B being 5 - 30 % (preferably 15 - 25).