Solid-state phase equilibria in the Co-Pt-Pr ternary system at 1173Â K

The solid-state phase equilibria in the Co-Pt-Pr ternary system at 1173 K (Pr ≤ 70%) were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) techniques. The 1173 K isothermal section consists of 15 single-phase regions, 24 two-phase regions and 10 three-phase regions. At 1173 K, we have observed that the maximum solid solubility of Pt in Co17Pr2, Co5Pr, Co19Pr5, Co7Pr2, Co3Pr and Co2Pr is below 1 at.% and the maximum solid solubility of Co in PrPt, Pr3Pt2 and Pr7Pt3 is also below 1 at.%, but the maximum solubility of Co in PrPt5 and PrPt2 is 15 and 7.5 at.%, respectively, and the homogeneity range for the PrPt2 phase is between approximately 24.2% and 31.7 at.% Pr; the maximum solubility of Pr in α-(Co, Pt) is below 1.5 at.%. In this work, it is found that the phase Pr3Pt4 does not exist in the ternary system. No any new ternary compounds were observed.