Influence of Fe substitution on the stability of Pr3Pt4compound

ABSTRACTThe stability of the phase Pr3Pt4in a series of Pr42.9Pt57.1-xFex(x = 0, 1, 2, 3) alloys was investigated by using X-ray diffraction (XRD) and differential thermal analysis (DTA). It was found that the phase Pr3Pt4(3:4 phase) with Pu3Pd4-type structure formed in the Pr42.9Pt57.1-xFexalloy for x = 0 annealed at 1173 K for two weeks. However, the fraction of the 3:4 phase decreased rapidly with increasing x, and approached zero when x = 3. XRD and DTA results showed that the 3:4 phase decomposes gradually into the two neighboring phases PrPt (1:1 phase) and (Pr, Fe)Pt2(1:2 phase), and the decomposition temperature of the reaction 3:4 → 1:1 + 1:2 is shifted slightly to higher temperature with increasing x. The reason for this phase decomposition is briefly discussed by the preferential site occupation of Fe in Pr3Pt4.