Influence of Co and Zr Content on Creation of Crystalline Phases in Rapidly-Cooled, Injection-Cast Alloys Fe70Zr8-xCoxNb2B20 (where x = 0, 2, 4, 6 or 8)

Rapid solidification techniques allow the manufacture of nanocrystalline alloys using a single-stage production process. There is an issue with the reproducibility of this process. However, careful selection of the chemical composition of the alloy allows a degree of control over the process. This paper presents the results of investigations into the structure and magnetic properties of rapidly-quenched alloys based on Fe. For these investigations, alloys with the compositions of Fe ₇₀Zr _8-xCo _xNb ₂B ₂₀(where x = 0, 2, 4, 6, or 8) were selected. The alloys were made using an injection-casting method. The structure of the obtained alloys was investigated using X-ray diffractometry. Utilising dedicated software, the crystalline phases within the volume of the samples were identified - as the magnetic phases of Fe ₂₃B ₆, αFe, and Fe ₂B. The magnetic properties of the produced alloys were determined on the basis of measurements of the magnetic polarisation curves as a function of temperature, and the static hysteresis loops. The thermomagnetic curves confirmed the existence of the Fe ₂₃B ₆phase within the volume of two samples. The values of the saturation magnetisation and coercive field were determined from the static hysteresis loops. The alloys in which the presence of the Fe ₂₃B ₆phase was detected (alloy compositions Fe ₇₀Zr ₄Co ₄Nb ₂B ₂₀and Fe ₇₀Zr ₂Co ₆Nb ₂B ₂₀) were found to exhibit soft magnetic properties. A progressive decline in the presence of the Fe ₂B phase within the investigated alloys was observed with increasing Co content (at the expense of Zr content). On the basis of the performed investigations, the major influence of the Co and Zr content on the creation process of the crystalline phases, during the rapid solidification process was confirmed.