Ball milling nanocrystallization of arc-melted and melt-spun Fe₇₈Co₅Nb₃Zr₃B₅Ge₅Cu₁ alloy: microstructure and magnetic properties

Abstract

The viability of developing a nanocrystalline microstructure for the Fe₇₈Co₅Nb₃ Zr₃B₅Ge₅Cu₁ composition using a planetary ball mill was studied. Two starting samples were chosen: an arc-melted ingot and a partially crystallized melt-spun ribbon. The α-Fe phase was detected in both initial samples, although different intermetallic phases were detected in each of them. Milling at 150 rpm, these intermetallics disappeared after 5 h for the melt-spun alloy (RQ) and did not disappear even after 70 h for the arc-melted sample (AM). However, the α-Fe phase became nanosized in both cases. A good thermal stability was found for the RQ alloy after 10 h of milling, although the nanocrystal size increased from ∼8 to ∼20 nm after heating to 973 K. The AM samples exhibited a lower coercivity and a higher magnetization than RQ samples.

Acknowledgements

This work was supported by the Spanish Government and EU FEDER (Project MAT 2004-04618). J.S. Blázquez acknowledges a research contract from the Regional Government of Andalucía (Spain).