Structure and Magnetic Properties of the Fe-Cu-Nb-Si-B Powder Prepared by Milling

Abstract

We have studied the influence of milling on the structure and magnetic properties of Fe73.5Cu1Nb3Si13.5B9 powder prepared in a vibratory micro-mill as a function of a long the milling time. Three powder samples were prepared and investigated (one prepared by the milling of an amorphous ribbon, one by the milling of the same ribbon in a partially nanocrystallized state and one by the milling of pure elements). The structural analysis showed a decrease in the grain size with the increasing time of milling. The average grain size was found to be in the range from about 8 μm after 200 hours of milling down to below 1 μm after 1700 hours. The coercivity of the samples prepared from pure elements increased almost linearly up to 1700 hours of milling while further milling lead to the saturation at 25 kA/m (at the milling time of 3500 hours). The coercivity of the samples milled from ribbons increased to its maximum of 8 kA/m for the milling time of 800 hours and then decreased.