This paper presents a discussion of the processing and characterization of alloy Co87Nb46B15 produced by rapid solidification, in which characterization techniques such as X-Ray Diffraction (XRD), scanning electron microscopy and spectroscopy Dispersion Energy (SEM / EDS) and magnetic properties were used, with the study of hysteresis curve. Several researches have been making on nanocrystalline materials, especially cobalt-base alloys, because of their thermodynamic stability, characterization and processing. Amorphous alloys have a structure of ultrafine, homogeneous grains with small crystal clusters in amorphous phase.