STRUCTURAL IDENTIFICATION OF A MELT-SPUN HF-NI NANOCRYSTALLINE ALLOY

The melt-spinning technique was used to prepare a nanocrystalline (nc) Hf11Ni89 ribbon. Both electron and X-ray diffraction show that the as -quenched sample is HfNi5 single-phased with a grain size about 10 nm. The measurement of its magnetic properties indicate that a partial fe rromagnetic phase corresponding to about 0.5% pure Ni precipitate exis ts in the as-quenched sample, while the HfNi5 matrix is paramagnetic a t least down to 5 K. Since diffraction techniques including high-resol ution electron microscopy were unable to reveal the existence of anoth er distinct phase, this small ferromagnetic magnetization component ca n be tentatively ascribed to a Ni-enriched interfacial phase. The magn etic characteristics of this phase were found to have normal distribut ions, indicating that there is no special factor to dominate its forma tion. (C) 1997 Acta Metallurgica Inc.