Cerium-iron-based magnetic compounds

Patent metadata

Field	Value
Publication number	US-9548150-B2
Application number	US-201313786807-A
Country	US
Kind code	B2
Filing date	Mar 6, 2013
Priority date	Mar 6, 2013
Publication date	Jan 17, 2017
Grant date	Jan 17, 2017

Abstract

New magnetic materials containing cerium, iron, and small additions of a third element are disclosed. These materials comprise compounds Ce(Fe 12−x M x ) where x=1-4, having the ThMn 12 tetragonal crystal structure (space group I4/mmm, #139). Compounds with M=B, Al, Si, P, S, Sc, Co, Ni, Zn, Ga, Ge, Zr, Nb, Hf, Ta, and W are identified theoretically, and one class of compounds based on M=Si has been synthesized. The Si cognates are characterized by large magnetic moments (4πM s greater than 1.27 Tesla) and high Curie temperatures (264≦T c ≦305° C.). The Ce(Fe 12−x M x ) compound may contain one or more of Ti, V, Cr, and Mo in combination with an M element. Further enhancement in T c is obtained by nitriding the Ce compounds through heat treatment in N 2 gas while retaining the ThMn 12 tetragonal crystal structure; for example CeFe 10 Si 2 N 1.29 has T c =426° C.

First claim

The invention claimed is:

1. A permanent magnet material containing the compound, Ce(Fe 12−x Si x ), having the tetragonal ThMn 12 crystal structure, space group I4/mmm, #139 and where x has a value in the range of one to four, the compound Ce(Fe 12−x Si x ), having been prepared from a melt consisting of cerium, iron, and silicon and the melt having been rapidly solidified at a cooling rate to form particles of a permanent magnet material containing the compound having the tetragonal ThMn 12 crystal structure, space group I4/mmm, #139, the particles of permanent magnet material having a magnetic moment value, 4πMs, in the range of 1.04 to 1.27 Tesla, the Ce(Fe 12−x Si x ) compound contains one or more of Ti, V, Cr, and Mo in combination with Si such that the combination provides a value of x in the range of 1-4 and Si comprises at least 0.1 x.

2. A permanent magnet material as stated in claim 1 and containing at least seventy percent by weight of the Ce(Fe 12−x Si x ) compound.

3. A permanent magnet material containing the compound, Ce(Fe 12−x Si x ), having the tetragonal ThMn 12 crystal structure, space group I4/mmm, #139 and where x has a value in the range of one to four, the compound Ce(Fe 12−x Si x ), having been prepared from a melt consisting of cerium, iron, and silicon and the melt having been rapidly solidified at a cooling rate to form particles of a permanent magnet material containing the compound having the tetragonal ThMn 12 crystal structure, space group I4/mmm, #139, the particles of permanent magnet material having a magnetic moment value, 4πMs, in the range of 1.04 to 1.27 Tesla, the Ce(Fe 12−x Si x ) compound containing nitrogen, Ce(Fe 12−x Si x )N y , the value of y being from one to three such that the nitrogen is present in an amount up to three nitrogen atoms per formula unit for increasing the Curie temperature, T c , of the material as compared with the T c of the same Ce(Fe 12−x Si x ) compound without the nitrogen.

4. A permanent magnet material as stated in claim 3 and containing at least seventy percent by weight of the crystalline Ce(Fe 12−x Si x )N y compound.

5. A permanent magnet material as stated in claim 1 in which the Ce(Fe 12−x Si x ) compound further containing nitrogen in an amount up to three nitrogen atoms per formula unit, the nitrogen being present in an amount for increasing the Curie temperature, T c , of the material as compared with the T c of the same Ce(Fe 12−x Si x ) compound without the nitrogen.

6. A permanent magnet material as stated in claim 2 in the form of a consolidated particle permanent magnet.

7. A permanent magnet material as stated in claim 4 in the form of a consolidated particle permanent magnet.

8. A permanent magnet material as stated in claim 5 in the form of a consolidated particle permanent magnet.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Zhou Chen
• Pinkerton Frederick E
• Herbst Jan F

Classifications

• H01F1/0593 Primary

  of tetragonal ThMn12-structure · CPC title