Nanocomposites and nanomaterials

The influence of Fe content on phase-structural state of Sm2Co17 compound during hydrogen-vacuum treatment
Trostianchyn A.M.1,2, Bulyk I.I.2,3, Duriagina Z.A.1
1 Department of Materials Science and Engineering, Lviv Polytechnic National University. Bandera Str., 12, Lviv-79013, Ukraine.
E-mail: andrii.m.trostianchyn@lpnu.ua
2 Karpenko Physico-Mechanical Institute of the NAS of Ukraine, Naukova Str., 5, Lviv-79060, Ukraine.
3 Institute for Rare Earth Magnetic Materials and Devices (IREMMD), Jiangxi University of Science and Technology, Ganzhou, 341000, P.R. China

The formation of a textured nanostructured state in ferromagnetic materials based on rare-earth metal alloys, consisting of a mixture of magnetic soft and magnetic hard phase, allows to double the higher specific magnetic energy compared to modern magnets. The hydrogen-vacuum treatment by means of hydrogenation-disproportionation-desorption-recombination (HDDR) is a promising way for obtaining such structure in the result of hydrogen initiated phase transformations [1]. In its implementation, it is very important to ensure the presence of soft and hard magnetic phases in the final material to obtain high magnetic properties. One of the common methods of forming a two-phase state in Sm-Co system alloys is iron alloying, that significantly affects the magnetic properties, the change of which is different for SmCo5 and Sm2Co17 compounds [2]. Since most publications on this effect focus on SmCo5 compound, we investigated the features of HDDR in Sm2Co17-xFex (x = 2, 4, 6 та 8) alloys under hydrogen pressures 0.5; 2.0 and 4.0 MPa at a maximum heating temperature of 950 °C. The influence of Fe content on the phase state, microstructure and relative ratio of structural components in the initial alloys, as well as the evolution of these parameters during HDDR depending on the processing conditions are analyzed. The optimal Fe content in the initial Sm2Co17-xFex alloy is discussed from point of view of nanostructure formation after hydrogen-vacuum treatment.

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