Reuse of Fe-based amorphous alloys containing CRM: study on their temperature behavior

Abstract

In this paper, the physico chemical properties of Fe–based amorphous alloys containing critical raw materials (CRM) were investigated in order to reuse them for photocatalytic degradation of azo dyes. The iron-based metallic glasses were prepared by melt spinning method. Their chemical composition is: Fe67B14Co18Si, Fe78B15Mo2Si5 and Fe40B16Ni40Mo4. Characterization of the ribbons was done using combination of analytical methods. Studied materials were heated in inert atmosphere and in air at temperature of 1000 °C. Crystallization processes of investigated Fe–based amorphous alloys depending on their chemical composition were registered using thermal analysis. The changes of material phase composition and crystallinity degree were studied using powder X-ray diffraction (XRD) and Mössbauer spectroscopy (MS). The thermal treatment in inert atmosphere above the crystallization temperature of studied amorphous alloys result in rearrangement of iron neighbours and formation of multiphase crystalline structure, which strongly depends on the additive elements (Co, Ni, Mo). Heating of ribbons in air affects significantly the kinetic of crystallization and registered products in comparison to annealing in inert (argon) atmosphere. Investigation of thermal stability of ribbon metallic glasses and formation of different intermediate and product compounds is very important for practical application of damaged amorphous alloys, their further reuse and recycling.