Role of aluminium in structural and magnetic properties of nanocrystalline alloy FeSiBNbCu

The influence of partial substitution of Fe, Si and B elements by Al (up to 9%) is analyzed for a nanocrystalline FeSiBNbCu alloy. Structural studies show that the increment of Al deteriorates the glass forming ability of the material. Coercivity in amorphous as-quenched samples becomes lower as the Al content increases in two alloy series: while after nanocrystallization values as small as about 0.5 A/m are obtained. DSC thermograms show that addition of Al advances the nucleation of the crystalline phase. Also, a particular evolution is noticed when Si is replaced by Al: the exothermic peak characteristic of alpha-(Fe,Si) phase begins to split into two peaks while increasing the Al content.