Magnetic materials and permanent magnets

• US 5,645,651 A
• Filed: 06/07/1995
• Issued: 07/08/1997
• Est. Priority Date: 08/21/1982
• Status: Expired due to Term

• Current Assignee: Hitachi Metals (Thailand) Ltd.
• Original Assignee: Sumitomo Seika Chemicals Company Limited (Sumitomo Chemical Company Limited)
• Inventors: Matsuura, Yutaka, Sagawa, Masato, Fujimura, Setsuo
• Primary Examiner(s): Yee, Deborah
• Application Number:
  US08/485,183
• Time in Patent Office: 762 Days
• Field of Search: 420/121, 420/83, 148/302
• US Class Current: 148/302
• CPC Class Codes: C22C 1/0441 Alloys based on intermetallic compounds of the type rare earth - Co, Ni
• CPC Class Codes: H01F 1/057 and IIIa elements, e.g. Nd2Fe14B
• CPC Class Codes: H01F 1/0577 sintered

Abstract

Magnetic materials comprising Fe, B, R (rare earth elements) and Co having a major phase of Fe--Co--B--R intermetallic compound(s) of tetragonal systems and sintered anisotropic permanent magnets consisting essentially of, by atomic percent, 8-30% R (at least one of rare earth elements inclusive of Y), 2-28% B, no less than 50% Co, and the balance being Fe with impurities. Those may contain additional elements M (Ti, Ni, Bi, V, Nb, Ta, Cr, Mo, W, Mn, Al, Sb, Ge, Sn, Zr, Hf) providing Fe--Co--B--R--M type materials and magnets.

Claims

1. A crystalline R(Fe,Co)BXAM compound having a stable tetragonal crystal structure having lattice constants of a_o about 8.8 angstroms and c_o about 12 angstroms, in which R is at least one element selected from the group consisting of Nd, Pr, La, Ce, Tb, Dy, Ho, Er, Eu, Sm, Gd, Pm, Tm, Yb, Lu and Y, X is at least one element selected from the group consisting of S, C, P and Cu, A is at least one element selected from the group consisting of H, Li, Na, K, Be, Sr, Ba, Ag, Zn, N, F, Se, Te and Pb, and M is at least one element selected from the group consisting of Ti, Ni, Bi, V, Nb, Ta, Cr, Mo, W, Mn, Al, Sb, Ge, Sn, Zr, Hf and Si.

2. The crystalline compound of claim 1, wherein (Fe,Co) comprises Fe and Co, provided that Co is present in an amount up to 50 atomic % of the sum of Fe and Co.

3. The crystalline compound of claim 1, wherein (Fe,Co) comprises Fe and Co, provided that Co is present in an amount up to 100 atomic % of the sum of Fe and Co.

4. The crystalline compound of claim 1, wherein in the group (Fe,Co) Fe is not present.

5. The crystalline compound of claim 1, wherein in the group (Fe,Co) Co is not present.

6. The crystalline compound of claim 1, wherein X is C.

7. The crystalline compound of claim 1, wherein A is H.

8. The crystalline compound of claim 1, wherein X is not present.

9. The crystalline compound of claim 1, wherein A is not present.

10. The crystalline compound of claim 1, wherein M is not present.

11. The crystalline compound of claim 1, wherein A and M are not present.

12. The crystalline compound of claim 1, wherein X and A are not present.

13. The crystalline compound of claim 1, wherein X and M are not present.

14. The crystalline compound of claim 1, wherein X, A and M are not present.

15. The crystalline compound of claim 1, wherein M is selected from the group consisting of V, Si and Al.

16. The crystalline compound of claim 1, wherein X is C and M is Al.

17. The crystalline compound of claim 1, wherein X is C, M is Al and R is Nd and/or Dy.

18. The crystalline compound of claim 1, wherein said compound has a crystal size of at least 1 μ

m.

19. The crystalline compound of claim 1, wherein at least 50 atomic % of R is at least one element selected from the group consisting of Nd and Pr.

20. The crystalline compound of claim 1, wherein R is Nd.

21. The crystalline compound of claim 1, wherein R is at least one element selected from the group consisting of Nd, Pr, Tb, Dy and Ho.

22. The crystalline compound of claim 1 which has magnetic anisotropy.

23. The crystalline compound of claim 1 which has a Curie temperature of at least 310°

C.

24. The crystalline compound of claim 23, which has Curie temperature higher than a basic compound including no Co having a Curie temperature of at least 310°

C.