FORMATION, DECOMPOSITION, AND ELECTRICAL TRANSPORT PROPERTIES OF AMORPHOUS HF-NI AND HF-CO ALLOYS

Amorphous Hf1-xNix and Hf1-xCox alloys in the concentration range 0.2≤x≤0.9 were prepared by melt spinning. The crystallization behavior of these alloys was studied by means of differential scanning calorimetry and x-ray diffraction. At least two new compounds in the Hf-Ni system were observed to be formed upon crystallization of the amorphous alloys. The electrical resistivity (ρ) in the amorphous alloys and in crystalline HfNi5 was studied in the range from 4.2 to 300 K. Negative temperature dependences of ρ were observed in several of the amorphous alloys, extending from x=0.25 to x=0.65 in Hf1-xNi x. The thermal stability of the amorphous alloys is discussed in terms of a diffusion mechanism. The extended Ziman theory of liquid metals was used in the interpretation of the temperature dependence of the resistivity.