Phase Composition and Magnetic Properties of Nanostructured Fe–Co–Ni Powders

Abstract

Nanostructured Fe–Co–Ni powders, with crystallite sizes of 10–35 nm for different compositions, are obtained in the whole range of compositions (step change in the components content is of 10 wt.% and, in the case of near the phase boundaries, 3–5 wt.%) by the reduction of freshly co‐precipitated mixed hydroxides with hydrazine hydrate in a strongly alkaline medium. The isothermal section of the phase diagram corresponding to the synthesis temperature (363–368 K) is constructed using reflection modeling based on XRD data of the samples series with different compositions. Its features are founded, characterized, and discussed: the phase diagram of the system in the nanostructured and nonequilibrium state is compared with the phase diagram of the system in the bulk state. In the region of the FCC‐solid solution, the “lattice parameter–composition” dependence was described by the flat surface equation (three‐dimensional analog of Vegard's law). Some magnetic characteristics are measured for the Fe–Co–Ni systems containing 10 wt.% Ni and variable Co/Fe ratio. Some features of the superparamagnetic component are observed above the blocking temperature; they are related to the crystallite size and the phase composition of the samples.

Influence of NicoreAushell Nanoparticles’ Morphology on Their Magnetic Properties

“…All the discrepancies between the phase diagram of Au–Ni and the data described above and obtained by us − tell about the effective temperatures T eff , which are very specific to different bimetallic and triple metallic nanoparticles and depend on their size. These effective temperatures are due to the ones of the existence of the appropriate solid solutions in the phase diagrams.…”

“…Nevertheless, such a study is absent even for Ni/Co/Fe–Pt core Au shell nanoparticles since there is no their structure characterization in detail and the impact of structure on their magnetic properties in the observed papers. Obviously, Ni core Au shell nanoparticles are the most suitable to be under investigation because of their magnetic characteristics discussed in more detail − and there is the scrutiny of those nanoparticles. − …”

Impact of Iron on the Fe–Co–Ni Ternary Nanocomposites Structural and Magnetic Features Obtained via Chemical Precipitation Followed by Reduction Process for Various Magnetically Coupled Devices Applications

“…It is shown that when the nanocomposites reduced at 300 and 400 °C had an increase in iron content, the lattice period of the bcc- and fcc-nanocomposites increased. In different studies [ 31 , 32 , 33 ], the authors revealed the dependence of the value of the crystal lattice period of nanocomposites in the nanostructured systems Fe–Co–Ni. It is shown that in these systems, the lattice period of the bcc- and fcc-nanocomposites increased with an increase in the iron and cobalt content.…”

Electrolyte pH dependence of composition, roughness parameters, particle diameter and magnetic features of nanostructured Fe‐Co‐Ni/ITO deposits prepared by electrochemical deposition method

“…[6][7][8][9][10][11][12][13][14][15][16] Among them, nanostructured ternary ferromagnetic materials with different compositions have been widely studied and attracted great attention owing to their outstanding features suitable for various fields of nanotechnology and engineering. [16][17][18][19][20] To study and manufacture them, researchers use simulation and synthesis methods. Electrochemical deposition (ECD) method, which is one of the most effective and most preferred synthesis methods, is widely used for this purpose due to its many well-known superior features.…”

“…Therefore, to improve the physical property of interest, theoretical and experimental studies have focused more on binary and ternary alloys 6–16 . Among them, nanostructured ternary ferromagnetic materials with different compositions have been widely studied and attracted great attention owing to their outstanding features suitable for various fields of nanotechnology and engineering 16–20 . To study and manufacture them, researchers use simulation and synthesis methods.…”