Awais Ikram (Author), Muhammad Awais (Author), Richard Stuart Sheridan (Author), Allan Walton (Author), Spomenka Kobe (Author), Franci Pušavec (Author), Kristina Žužek Rožman (Author)

Abstract

Fully dense spark plasma sintered recycled and fresh HDDR Nd-Fe-B nanocrystalline bulk magnets were processed by surface grain boundary diffusion (GBD) treatment to further augment the coercivity and investigate the underlying diffusion mechanism. The fully dense SPS processed HDDR based magnets were placed in a crucible with varying the eutectic alloys Pr68Cu32 and Dy70Cu30 at 2-20 wt. % as direct diffusion source above the ternary transition temperature for GBD processing followed by secondary annealing. The changes in mass gain was analyzed and weighted against the magnetic properties. For the recycled magnet, the coercivity (HCi) values obtained after optimal GBDP yielded ~60% higher than the starting recycled HDDR powder and 17.5% higher than the SPS-ed processed magnets. The fresh MF-15P HDDR Nd-Fe-B based magnets gained 25-36% higher coercivities with Pr-Cu GBDP. The FEG-SEM investigation provided insight on the diffusion depth and EDXS analysis indicated the changes in matrix and intergranular phase composition within the diffusion zone. The mechanism of surface to grain boundary diffusion and the limitations to thorough grain boundary diffusion in the HDDR Nd-Fe-B based bulk magnets were detailed in this study.

Keywords

redki zemeljski trajni magneti;recikliranje;sintranje s plazmo;postopek difuzije meje zrn (GBDP);visoka magnetna koercivnost;rare earth permanent magnets;HDDR Nd2Fe14B;recycling;spark plasma sintering;grain boundary diffusion processing (GBDP);high coercivity;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL FS - Faculty of Mechanical Engineering
UDC: 537.6(045)
COBISS: 25316867 Link will open in a new window
ISSN: 1996-1944
Views: 159
Downloads: 67
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Other data

Secondary language: Slovenian
Secondary title: Omejitve pri procesiranju kristalnih mej recikliranega sistema HDDR Nd-Fe-B
Secondary keywords: redki zemeljski trajni magneti;recikliranje;sintranje s plazmo;postopek difuzije meje zrn (GBDP);visoka magnetna koercivnost;
Type (COBISS): Article
Pages: f. 1-17
Volume: ǂVol. ǂ13
Issue: ǂiss. ǂ16
Chronology: Aug. 2020
DOI: 10.3390/ma13163528
ID: 14259054