Characterization of magnetic FeCo particles with controlled bimetallic composition

In this study, six bimetallic FeCo particles were synthesized via the hydrothermal method, employing hydrazine hydrate as a reducing agent. These particles were synthesized at specific Fe:Co ratios of 1:0, 3:1, 1:1, 1:3, 1:9 and 0:1. The synthetic feeding of Fe:Co is of fundamental importance as it not only modulates the composition of the particles but also exerts control over their structural, morphological, and performance attributes. X-ray diffraction (XRD) analysis revealed that for particles synthesized from pure ferrous salt and pure cobalt salt, the former exhibited a Fe3O4 spinel structure, while the latter presented an hcp-type metallic Co structure. Conversely, for the remaining four Fe:Co synthetic feedings, the structure of FeCo bimetallic alloys exhibited a gradual transformation from an Fe-based bcc structure to a Co-based bcc structure, eventually culminating in a Co-based hcp structure as the Co content increased. Scanning electron microscopy (SEM) images indicated that particles prepared with a Fe:Co feeding ratio of 1:0 and 3:1 manifested as cube-shaped particles with approximate sizes of 200 nm and 100 nm, respectively. Particles synthesized with a 1:1 Fe:Co ratio exhibited pyramidlike shapes accompanied by small spinel structures. In contrast, those prepared with a 3:1 and 9:1 Fe:Co feeding ratio displayed a flower-like morphology with particle sizes around 10 mu m, while particles synthesized using pure cobalt salts assumed a palm frond-like appearance. Moreover, the investigation into thermal stability established that FeCo alloy particles exhibited superior resistance to air oxidation when compared to pure Co particles. The magnetic studies indicated that all the particles were paramagnetic materials, with their magnetic properties being contingent on the composition. Notably, the particles synthesized with synthetic feedings of 1:1 and 3:1 exhibited the highest saturation magnetization of 151.80 emu & sdot;g- 1 and the lowest saturation magnetization of 62.79 emu & sdot;g  1, respectively. These findings hold significant promise for the development of stable and finelytailored magnetic particles with diverse potential applications in technology.

Automated summary

In this study, six bimetallic FeCo particles were synthesized via the hydrothermal method at different Fe:Co ratios. The Fe:Co ratio not only modulates the composition of the particles but also influences their structure and magnetic properties. The FeCo alloys showed a transformation from an Fe-based structure to a Co-based structure with increasing Co content. The Fe:Co ratio of 1:1 and 3:1 resulted in particles with the highest and lowest saturation magnetization, respectively.