材料期刊网

The phase diagram of the Ho-Ni binary system was investigated by X-ray diffraction, differential thermal analysis, optical microscopy and electron probe microanalysis techniques. The existence of eight intermediate phases has been confirmed: Ho3Ni, Ho3Ni2, HoNi, HoNi2, HoNi3, HO2Ni7, HoNi5, and Ho2Ni17. The homogeneity region of the HoNi2 phase extends from 65.6 to 66.7 at.% Ni. The other phases are line compounds. No appreciable solid solubility of holmium in nickel or of nickel in holmium was observed. Ho3Ni2 exists in two structural modifications depending on the temperature. HoNi and HoNi5 melt congruently at 1060 and 1370-degrees-C respectively. There are seven peritectic reactions and three eutectic reactions in this system.