Phase equilibrium of the Gd–Fe–Co system at 873 K

Phase equilibrium of the ternary Gd–Fe–Co system at 873 K was investigated by using X-ray diffraction technique, electron probe microanalysis, metallographic analysis and differential thermal analysis. The 873 K isothermal section of the phase diagram of the Gd–Fe–Co ternary system consists of 11 single-phase regions, 16 two-phase regions and 6 three-phase regions. Three pairs of corresponding compounds of Gd–Co and Gd–Fe, i.e., Gd2Co17 and Gd2Fe17, GdCo3 and GdFe3, GdCo2 and GdFe2, form a continuous series of solid solution. The compound Gd2Co7−xFex was found to have a broad solubility range from 0 to 31 at.% Fe. The maximum solubility of Co in Gd6Fe23 is about 7 at.% Co. At 873 K, the maximum solubilities of Fe in Gd3Co and Gd4Co3 are about 3 and 1 at.% Fe, respectively. No ternary compound was found in all ternary alloy samples.