CRYSTALLIZATION OF AMORPHOUS IRON-NICKEL-PHOSPHORUS ALLOYS PREPARED BY ELECTRODEPOSITION

The crystallization behaviour of amorphous Fe-Ni-P alloy electrodeposi ts has been studied over a wide range of compositions using both isoth ermal and dynamic annealing methods. X-ray and electron diffraction al ong with microhardness measurements were used to monitor the crystalli zation process. Isothermal crystallization kinetics suggests mainly a growth process on pre-existing random nuclei. No evidence of metastabl e intermediate phases was found in isothermally crystallized alloys. T he activation energy for crystallization is very sensitive to the phos phorus content of the alloys. The decrease in the activation energy an d enthalpy for crystallization imply a greater degree of supersaturati on with increase in the phosphorus content. Both enthalpy and activati on data suggest that 10 wt.% phosphorus is the critical concentration to obtain an amorphous rather than microcrystalline structure. (C) 199 7 Elsevier Science S.A.