Thermomagnetic gravimetric study of the crystallization process in amorphous Fe-Si-B-Cu alloys

The thermal properties of amorphous Fe84-xSi6B10Cux and Fe77.5-xSi13.5B9Cux alloys have been investigated using thermomagnetic gravimetry (TMG). After electronically cancelling the sample weight, an apparent weight (AW) was applied by placing a magnet beneath the sample pan. Heating was then carried out to detect the formation of ferromagnetic crystallization-induced phases. In both Cu-free Fe84Si6B10 and Fe77:7Si13:5B9 alloys, a two-stage increase in AW was observed on the TMG curve. The addition of Cu to these alloys caused a decrease in the crystallization temperatures as well as a marked increase in AW in the above two-stage process. It is presumed that such behaviour originates from the lack of metalloid elements in the amorphous matrix, which is caused by their distribution to Cu-enriched clusters.