The isothermal section of the phase diagram of the Dy–Er–Co ternary system at 773 K

The isothermal section of the phase diagram of the Dy–Er–Co ternary system at 773 K was investigated by X-ray powder diffraction (XRD), differential thermal analysis (DTA) and optical microscopy. The result shows that this section consists of 9 single-phase regions and 8 two-phase regions, and no three-phase region. The compounds Dy 2Co 17 and Er 2Co 17, Dy 2Co 7 and Er 2Co 7, DyCo 3 and ErCo 3, DyCo 2 and ErCo 2, Dy 4Co 3 and Er 4Co 3, Dy 12Co 7 and Er 12Co 7, Dy 3Co and Er 3Co form a continuous series of solid solutions. In addition, the single phases Dy and Er also form a continuous series of solid solution. The binary compounds DyCo 5 and ErCo 5 were not observed at 773 K. No ternary compound was found.