AP-FIM Analysis of Partitioning of Alloying Elements between Spinodally-decomposed Phases in Fe-Cr-Co-Si Alloys

Abstract

Partition of alloying elements between spinodally-decomposed phases in Fe-Cr-Co-Si alloys was examined by Atom-Probe Field-Ion Microscope (AP-FIM). The results showed that the ferromagnetic particle (α₁) is rich in Fe and Co, and the weak-ferromagnetic matrix (α₂) rich in Cr and Si. The enrichment of Si in the α₂ phase was explained through thermodynamical considerations. Si is more strongly bonded to Cr than to Fe. The improvement of hard magnetic properties by Si additions was found and discussed in terms of the changes in saturation magnetization of the α₁ and α₂ phases. The increase in coercive force may be mainly attributed to the reduction of saturation magnetization of the α₂ phase by the addition of Si.