Abstract: The thermal stability of amorphous Ni-RE-P (RE=Y, Ce, Sm) alloy has been studied by differential scanning calorimetry (DSC) in this paper. X-ray diffraction (XRD) and scanning electron microscope(SEM) were used to examine the structure change of the samples heated at different temperatures. The results showed that a small amount of rare earth elements(Y, Ce, Sm) added into amorphous Ni-P alloy could considerably enhanced the thermal stability of amorphous Ni-RE-P alloy. For example, only one exothermic peak appeared at 629 K for Ni-P, while the temperature of maximum exothermic peak which was regarded as crystallization of amorphous Ni-Y-P, Ni-Ce-P and Ni-Sm-P alloys was at 786 K, 795 K and 742 K respectively. With increasing of the treatment temperature, the amorphous Ni-P and Ni-RE-P alloys were progressively crystallized to be simultaneous with presentation of the fine crystals Ni and Ni_3P and the fine crystals grew up to greater crystalline particles due to aggregation of them in the bulk.
It was showed that the value of activation energy of the crystallization of Ni-RE-P was much greater than that of Ni-P, this indicated that the crystallization of Ni-RE-P was more difficult than that of Ni-P. A small amount of rare earth element (Y, Ce, Sm) played an important role in enhancing the thermal stability of amorphous Ni-RE-P alloy.

Key words: Rare earth(Y、Ce、Sm), Amorphous alloy(Ni-P), Thermal stability, Activation energy, DSC