In the last years the enhanced research of alternatives to permanent magnets with rare earth elements has been strengthened by economic reasons and an increasing demand of permanent magnets. On the search for new magnetic materials, which are able to compete the current permanent rare earth magnets, Co and Fe containing binary and ternary compounds with a promising high magnetocrystalline anisotropy seems to be a substantial solution. (Fe,Co)2-3B based alloys are a potential candidate for novel hard magnetic applications in consequence of a high magnetocrystalline anisotropy constant of about K1 = 0.41 MJ/m3. This thesis describes the synthesis and the analysis of the phase relations in various microcrystalline alloys with a nominal composition of (Fe1-xCox)71B29 (0 - x - 1). Initially, cast ingots have been synthesized by induction melting in inert atmosphere using master alloys. Furthermore, the ribbon casting process was realized with a melt-spinning facility and thereby the specimen got melted and were prepared with different wheel speeds of 18.9 m/s, 23.6 m/s, 26.7 m/s, 33 m/s and 37.7 m/s. Afterwards the melt-spun ribbons of selected compositions got a further heat treatment. For the purpose of determining the magnetic properties the alloys were analysed at room temperature by vibrating sample magnetometer (VSM). To characterize the phase relations of selected alloys, a powder X-ray diffraction was used. The cast material and selected melt-spun ribbons were investigated by field emission gun scanning electron microscope (FEGSEM) to study the microstructure of the alloys. In addition, samples were prepared by conventional ion milling and subsequently analysed by using a transmission electron microscope (TEM). The best hard magnetic properties were obtained for the (Fe0.7Co0.3)71B29 alloy at 26.7 m/s.