Bulk amorphous Pd-Ni-Fe-P alloys: Preparation and characterization

Bulk amorphous alloys of PdxNiyFe80-x-yP20 (25 less than or equal to x less than or equal to 60, 20 less than or equal to y less than or equal to 55, x + y greater than or equal to 60) were prepared by a flux-melting and water-quenching method. Seven-mm diameter glassy rods of Pd40Ni40-xFexP20 (0 less than or equal to x less than or equal to 20) were studied in greater detail. For these alloys, the difference between the crystallization and glass transition temperatures ranges from 102 K for x = 0 to 53 K for x = 20. In this composition range, the reduced glass transition temperature, T-rg, ranges from 0.66 to 0.57. The change in density upon crystallization ranges from 0.24 +/- 0.04% for x = 0 to 1.33 +/- 0.24% for x = 10. The partial molar volume of Fe in amorphous Pd40Ni40-xFexP20 alloys is significantly larger than the molar volume of (metastable) fee Fe. This, as well as a comparison with the molar volumes of crystalline compounds, suggests chemically selective Fe-Pd bonding in these glasses.