Annealing crystallization and catalytic activity of ultrafine NiB amorphous alloy

摘要

Annealing crystallization of ultrafine NiB amorphous alloy prepared by the chemical reduction method was studied by DTA, XRD and XAFS techniques. The XRD and XAFS results have revealed that the crystallization process of ultrafine NiB amorphous alloy proceeds in two steps. First, ultrafine NiB amorphous alloys is crystallized to form metastable nanocrystalline Ni_3B at an annealing tem- perature of 325 deg. C. Second, the nanocrystalline Ni_3B is fur- ther decomposed into crystalline Ni at 380 deg. C or higher tempera ture, the local structure around Ni atoms in resul- tant product is similar to that in Ni foil.