Effects of partial substitution of V and Ti for Fe on nitrogenation rate and magnetic properties of Sm2Fe17Nx anisotropic coarse powders

Ito, Mikio; Majima, Kazuhiko; Shimuta, Toru; Katsuyama, Shigeru

doi:10.1016/s0925-8388(02)00913-1

Cited by 11 publications

(6 citation statements)

References 12 publications

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“…3,11,13 It is also known that similar coercivity enhancement phenomena can be observed when Cr, Ti, V are added to Sm-Fe-N powder. [14][15][16] However, there was a drawback that remanence and squareness are significantly degraded when coercivity is reasonably enhanced by increasing x. The primary reason of this degradation has been attributed to the randomized orientations of the individual nanocrystalline cells for overnitrided powder (x > 5.5).…”

Section: Introductionmentioning

confidence: 99%

Multi-scale electron microscopy of overnitrided Sm-Fe-Mn-N powder

Hosokawa

Takagi

2018

AIP Advances

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Multi-scale electron microscopy technique that combines transmission electron microscopy (TEM) and focused ion beam - scanning electron microscopy (FIB-SEM) was utilized to investigate the influences of the change in microstructure of Sm2(Fe0.95Mn0.05)17Nx by overnitridation on the magnetic properties. The recent high-contrast backscatter electron imaging technique in SEM machines enabled us to reveal the formation events of cell-like microstructure from a quite large field of view. In addition, detailed TEM observations revealed the crystallographic orientations of the cells as well as the local chemical fluctuation. The combination of these techniques allows us to understand the microstructural hierarchy in this material, verifying that the original orientations of the individual particles are inherited to the nanocrystalline cells formed by overnitridation.

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Section: Introductionmentioning

confidence: 99%

Multi-scale electron microscopy of overnitrided Sm-Fe-Mn-N powder

Hosokawa

Takagi

2018

AIP Advances

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“…A group at Sumitomo Metal Mining reported that a high-performance powder with (BH) max = 175 kJ/m 3 was obtained with an Sm 2 (FeMn) 17 N x system by combining crushing treatment after overnitriding, and this powder was actually commercialized. Although the coercivity of the Sm 2 Fe 17 N 3 powder produced by the pulverization method was drastically reduced when exposed to a high temperature environment of about 200 °C, it is noteworthy that the overnitrided coarse powder exhibited excellent thermal stability (Iseki T. et al, 2003;Ito M. et al, 2003;Ito M. et al, 2002;Majima K. et al, 1997;Ohmori K. et al, 2006).…”

Section: Gas Reactionmentioning

confidence: 99%

Recent Research Trend in Powder Process Technology for High-Performance Rare-Earth Permanent Magnets

Takagi

Hirayama

Okada

et al. 2023

KONA

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Higher performance is constantly required in rare earth permanent magnets, which are an indispensable component of the motors of electric vehicles. When producing sintered magnets, advanced structural control is necessary in the powder metallurgy process in order to achieve high performance. Especially in recent years, it has become important to develop processes for Sm-Fe-N magnets and metastable phase magnets as next-generation magnets to replace the Nd-Fe-B magnets. Because the crystal grain refinement of sintered magnets is most effective for improving coercivity, production methods for raw powders have evolved from the traditional pulverization to chemical synthesis approaches, and as a result, a submicron-sized Sm-Fe-N powder with huge coercivity has been developed. State-ofthe-art physical synthesis methods have also been applied successfully to the synthesis of nanopowders. Since control of the grain boundary is very effective in Nd-Fe-B magnets, this approach has also been evolved to Sm-Fe-N magnets by nano coating. On the other hand, since technologies for crystalline orientation control and high-density sintering are indispensable for improvement of remanence, new low-thermal load consolidation techniques such as spark plasma sintering are being developed for Sm-Fe-N magnets and metastable phase magnets in order to overcome the inherent low thermal stability of these materials.

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“…At present, the Sm 2 Fe 17 N d compounds are mostly used for preparing bonded magnets due to its decomposition (Sm 2 Fe 17 N d -SmFe+a-Fe) at high temperatures [1][2][3][4][5]. However, the Sm 2 Fe 17 N d thin films have advanced as promising magnets because of the large saturation magnetization, large magnetic anisotropy, and a high Curie temperature of the Sm 2 Fe 17 N d compounds [6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%