Preparation and crystallization of Fe-Co-B amorphous powder

Abstract

Ultrafine (Fe_0.7Co_0.3)_100−x B _x amorphous powders with boron contentx 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 μm. 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 Mössbauer, X-ray and differential scanning calorimetry measurements indicates that there are two steps in the crystallization process. These steps represent the formation of α-Fe₇₀Co₃₀ phase and Fe₂B-like phase, respectively.