Nanocrystallisation of amorphous alloys based on iron

In the present paper, the FeCu1–X–Si13B9 alloys (X=Zr, Cr) were investigated by making use of different experimental techniques: X-ray diffraction, HREM, magnetic and electric measurements (permeability, coercive field, magnetisation, electrical resistivity). It is shown that soft magnetic properties of all examined alloys can be optimised by applying well-defined thermal annealing (magnetic permeability increases more than 20 times). This effect can be attributed to the formation of a nanocrystalline phase αFe(Si) with a mean grain size from 10 to 30 nm. The optimisation annealing temperature depends on the atomic radius of the alloying additions. In the case of the Fe74Cu1Cr1Zr2Si13B9 alloy, interaction of Zr and Cr atoms causes an increase of 1-h optimisation annealing temperature Tap of more than 200 K compared to Tap of Fe74Cu1Cr3Si13B9.