a Department of Physics Education, Chosun University, Kwangju 501-759, South Korea
b Institute for Materials Research, Tohoku University, Sendai 980, Japan
Abstract:
Nanocrystalline Al60Ni40 and Ni have been obtained by rod milling Al and Ni powder mixtures and chemical leaching Al atoms from the rod-milled Al60Ni40, respectively. The rod-milled alloy powders retained their bcc structure after being treated at room temperature and at 85 °C with a 25–30 wt.% KOH solution. The leached powders are very active and easily explode when they come into contact with air. The leached powders were transformed to a ferromagnetic fcc phase at high temperature. On cooling of the specimen from 600 °C, spontaneous magnetization M sharply increased at about 350 °C, indicating that the bcc phase was transformed to an fcc phase. It has been confirmed that the leaching temperature and annealing temperature and KOH concentration have a considerable effect on structural and magnetic properties.