Some aspects of the precipitation of Feα crystallites in the FePC amorphous alloy

The precipitation of Fe_α in some FePC amorphous alloys has been followed in situ by using neutron diffraction with a multidetector covering 80° (2θ). The quantity of Fe_α which precipitates before the final crystallization of the remaining amorphous phase is a function of the composition of the alloy but is independent of the heating rate. The alloy tends toward a mixture of Fe_α + am′ whose composition is about Fe₇₅(PC)₂₅. The crystallization of am′ occurs as soon as the excess of iron in the amorphous matrix is precipitated. We conclude that the excess of iron stabilizes the amorphous phase.