Magnetic evidence for structural-phase transformations in Fe-Co alloy nanocrystals produced by a carbon arc

Abstract

In previously reported work FexCo1−x[C] (x=0.0, 0.2, 0.4, 0.5, 0.6, and 0.8 nominally) nanoparticles were prepared by a Kratschmer–Huffman carbon-arc method. Fe0.5Co0.5[C] exhibited the largest magnetizations heretofore observed in similarly produced nanoparticles. Here we present a more detailed study of the magnetic properties of Fe0.5Co0.5[C] nanocrystals. Magnetic hysteresis loops have been measured to temperatures exceeding 1050 K. This is attributed to rotational processes in monodomain particles and is shown to be sensitive to ordering of the particles. Low-field thermomagnetic data clearly show features which we attribute to the α→α′ disorder–order and α→γ phase transformations, respectively.

Magnetic and structural studies of mechanically alloyed (Fe50Co50)62Nb8B30 powder mixtures

“…Fe-Co soft magnetic alloys show excellent magnetic properties such as low coercivity, H c , high saturation magnetisation, M s , and high Curie temperature, T c , that make them potential candidates for the high temperature applications [11][12][13][14]. However, too high additions of Nb (or similar elements) although favourable for thermal stability and grain size refinement, can be disadvantageous because of the important decrease in Curie temperature of the matrix [15].…”

Media effects on nanobrass arc fabrications

“…Nanocrystalline intermetallic compounds ␥-Cu 5 Zn 8 and -CuZn 5 are prepared by the laser vaporization controlled condensation technique [26]. Conventional gas condensation and carbon arc synthesis methods have not been successful for preparing such intermetallics, perhaps due to the limitation set by the melting temperature of crucible material used in these methods [36,37]. In this paper, we report a novel comparison of arc discharge productions of nanobrass (Cu/Zn alloys) and nanostructured Cu/ZnO, from a brass rod, in different media.…”

Electric-field-enhanced crystallization of amorphous Fe86Zr7B6Cu1 alloy

“…This coupling depends upon the volume fraction and grain size of crystallites. The increase of the volume fraction and the unrelated decrease of the grain size are both desirable microstructure [3][4][5].…”