METASTABLE BCC AND AMORPHOUS NI PRODUCED BY MECHANICAL ALLOYING AND CHEMICAL LEACHING

B.c.c. and amorphous Ni are obtained by a technique combining mechanic al alloying of Ni and Al elemental powders, and chemical leaching of A l in basic solution. The as-milled and milled-and-leached specimens ar e characterized by X-ray diffraction, transmission electron microscopy , high pressure differential thermal analysis, differential scanning c alorimetry and magnetization measurements. B.c.c. and amorphous Ni pha ses exhibit paramagnetic characters at low temperatures and transform to the ferromagnetic f.c.c. Ni phase at high temperatures. Low tempera ture, specific heat measurements indicate the enhancement of its elect ronic coefficient in the paramagnetic b.c.c. and amorphous Ni in compa rison with that of annealed f.c.c. Ni.