Effect of metalloid additives on the effectiveness of ultra-rapid annealing in Fe-B based nanocrystalline alloys

The effects of metalloid additives (ML = B, C, Si and P) on the structural and magnetic properties were investigated for nanocrystalline Fe86-xB14MLx alloys prepared by ultra -rapid annealing (URA) of melt-spun ribbons. It was found that the effectiveness of URA was affected by these elements and the soft magnetic properties after URA were degraded. Contrarily, addition of 1 at% Cu was found to be effective in enhancing the effectiveness of URA and coercivity (Hc) after URA was reduced significantly by Cu addition. These effects of additives on the soft magnetic properties after URA were well understood by considering the activation energy of crystallization.