Process for manufacturing a magnetic component made of an iron-based soft magnetic alloy having a nanocrystalline structure

A process for manufacturing a magnetic component comprising an iron-based soft magnetic alloy having a nanocrystalline structure the chemical composition of which is, in at. %, Fe.gtoreq.60%, 0.1%.ltoreq.Cu.ltoreq.3%, 0%.ltoreq.B.ltoreq.25%, 0%.ltoreq.Si.ltoreq.30%, and at least one element selected from the group consisting of niobium, tungsten, tantalum, zirconium, hafnium, titanium and molybdenum in proportions of between 0.1% and 30%, the balance being impurities resulting from smelting, the chemical composition furthermore satisfying the relationship 5%.ltoreq.B+Si.ltoreq.30%, comprising the steps of:

• providing an amorphous ribbon comprising the iron-based soft magnetic alloy,
• winding the ribbon around a mandrel to form a core and provide a blank for a magnetic component,
• and subjecting the blank to a crystallization heat treatment comprising at least one annealing step at a temperature of between 500.degree. C. and 600.degree. C. for a time of between 0.1 and 10 hours so as to cause nanocrystals to form, wherein, before the crystallization heat treatment, a relaxation heat treatment is carried out at a temperature below the temperature for the onset of recrystallization of the amorphous alloy,
• wherein the relaxation heat treatment is a temperature hold carried out for a time of between 0.1 and 10 hours at a temperature of between 250.degree. C. and 480.degree. C.