PREPARATION AND CRYSTALLIZATION OF FE-CO-B AMORPHOUS POWDER

Ultrafine (Fe0.7Co0.3)100-xBx amorphous powders with boron content x in the range 27-40 at % have been prepared by borohydride reduction. The preparation process shows that the powders have a catalysis property. The results of X-ray and electron diffractions show that all of the samples were spherical amorphous particles of dimension < 0.2 mum. The difference in the ease of composition between Fe-Co-B powder and ribbon indicates that the local environment of Fe-Co-B powder may be different from that of Fe-Co-B ribbon. The study of crystallization behaviour using Mossbauer, X-ray and differential scanning calorimetry measurements indicates that there are two steps in the crystallization process. These steps represent the formation of alpha-Fe70Co30 phase and Fe2B-like phase, respectively.