US 11,990,259 B2
Rare earth-iron-nitrogen-based magnetic powder, compound for bonded magnet, bonded magnet, and method for producing rare earth-iron-nitrogen-based magnetic powder
Satoshi Sugimoto, Sendai (JP); Masashi Matsuura, Sendai (JP); Takashi Ishikawa, Iwanai-gun (JP); and Yukinobu Yoneyama, Iwanai-gun (JP)
Assigned to TOHOKU UNIVERSITY, Sendai (JP); and SUMITOMO METAL MINING CO., LTD., Tokyo (JP)
Appl. No. 18/013,072
Filed by Tohoku University, Sendai (JP); and SUMITOMO METAL MINING CO., LTD., Tokyo (JP)
PCT Filed Mar. 31, 2021, PCT No. PCT/JP2021/013896
§ 371(c)(1), (2) Date Dec. 27, 2022,
PCT Pub. No. WO2022/004081, PCT Pub. Date Jan. 6, 2022.
Claims priority of application No. 2020-111144 (JP), filed on Jun. 29, 2020.
Prior Publication US 2023/0245807 A1, Aug. 3, 2023
Int. Cl. H01F 1/053 (2006.01); B22F 1/05 (2022.01); B22F 1/10 (2022.01); C08K 9/02 (2006.01); C22C 38/00 (2006.01); H01F 1/055 (2006.01); H01F 1/059 (2006.01)
CPC H01F 1/0551 (2013.01) [B22F 1/05 (2022.01); B22F 1/10 (2022.01); C08K 9/02 (2013.01); C22C 38/001 (2013.01); C22C 38/005 (2013.01); B22F 2301/355 (2013.01); B22F 2304/10 (2013.01); C08K 2201/005 (2013.01); C08K 2201/01 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A rare earth-iron-nitrogen-based magnetic powder comprising a rare earth element (R), iron (Fe), and nitrogen (N) as main constituents,
the magnetic powder having an average particle size of 1.0 μm or more and 10.0 μm or less and having a rare earth element (R) content of 22.0% by mass or more and 30.0% by mass or less and a nitrogen (N) content of 2.5% by mass or more and 4.0% by mass or less,
the magnetic powder comprising magnetic particles comprising: a core having a crystal structure selected from the group consisting of Th2Zn17-type, Th2Ni17-type, and TbCu7-type crystal structures; and a shell layer having a thickness of 1 nm or more and 30 nm or less and provided on a surface of the core,
the shell layer containing a rare earth element (R) and iron (Fe) in an atomic ratio R/Fe of 0.3 or more and 5.0 or less and having a nitrogen (N) content of more than 0 at % and 10 at % or less,
the magnetic powder further comprising particles of a compound comprising a rare earth element (R) and phosphorus (P).