Issues »  Volume 36, Issue 7

Peculiarities of the HDDR Processes at Low Hydrogen Pressures in Nd—Fe—B System Alloys

I. I. Bulyk$^{1}$, А. M. Trostianchyn$^{1}$, V. V. Burkhovetskyi$^{2}$, V. Yu. Tarenkov$^{2}$

$^{1}$Karpenko Physico-Mechanical Institute, NAS of Ukraine, 5, Naukova Str., 79060 Lviv, Ukraine
$^{2}$Donetsk Institute for Physics and Engineering Named after O.O. Galkin, NAS of Ukraine, 72 R. Luxembourg Str., 83114 Donetsk, Ukraine

Received: 22.04.2013; final version - 05.06.2014. Download: PDF

The features of hydrogenation, disproportionation, desorption, recombination (HDDR) processes in Nd$_{11.8}$Fe$_{82.3}$B$_{5.9}$ and Nd$_{16}$Fe$_{76}$B$_{8}$ alloys under hydrogen pressure of 0.05 MPa in the temperature range of 20—840°C are studied by means of differential thermal analysis (DTA), X-ray diffraction analysis and scanning electron microscopy (SEM) methods. Superfine Nd$_{2}$Fe$_{14}$B phase with up 200 nm thickness lamellar microstructure is formed in some alloys’ areas after solid HDDR under low hydrogen pressure. The principal possibility of fine-grained magnetic-anisotropy microstructure formation in Nd—Fe—B system alloys is shown in the cases of presence of small amount of initial ferromagnetic Nd$_{2}$Fe$_{14}$B phase among disproportionated products.

Key words: hydrogen initiated phase transformations, magnetic anisotropy, ferromagnetic alloys, Nd$_{2}$Fe$_{14}$B, hydrogen technology.

URL: http://mfint.imp.kiev.ua/en/abstract/v36/i07/0903.html

DOI: https://doi.org/10.15407/mfint.36.07.0903

PACS: 61.72.Ff, 75.30.Gw, 75.50.Tt, 75.50.Ww, 75.75.Cd, 81.07.Wx, 81.40.Rs

Citation: I. I. Bulyk, А. M. Trostianchyn, V. V. Burkhovetskyi, and V. Yu. Tarenkov, Peculiarities of the HDDR Processes at Low Hydrogen Pressures in Nd—Fe—B System Alloys, Metallofiz. Noveishie Tekhnol., 36, No. 7: 903—916 (2014) (in Ukrainian)

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