(19)
(11) EP 0 258 609 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
26.04.1989 Bulletin 1989/17

(43) Date of publication A2:
09.03.1988 Bulletin 1988/10

(21) Application number: 87110634.0

(22) Date of filing: 22.07.1987
(51) International Patent Classification (IPC)4: H01F 1/053
(84) Designated Contracting States:
DE FR GB

(30) Priority: 23.07.1986 JP 172987/86
07.08.1986 JP 185905/86
14.10.1986 JP 243490/86
06.01.1987 JP 85787/87

(60) Divisional application:
90121313.2 / 0421488

(71) Applicant: HITACHI METALS, LTD.
Chiyoda-ku, Tokyo 100 (JP)

(72) Inventors:
  • Tokunaga, Masaaki
    Fukaya-shi Saitama (JP)
  • Endoh, Minoru
    Kumagaya-shi Saitama (JP)
  • Kogure, Hiroshi
    Kumagaya-shi Saitama (JP)

(74) Representative: Strehl Schübel-Hopf Groening & Partner 
Maximilianstrasse 54
80538 München
80538 München (DE)


(56) References cited: : 
   
       


    (54) Permanent magnet with good thermal stability


    (57) A permanent magnet having good thermal stability, consisting essentially of the composition represented by the general formula:


    wherein R is Nd alone or one or more rare earth elements mainly composed of Nd, Pr or Ce, 0≦x≦0.7, 0.02≦y≦0.3, 0.001≦z≦0.15 and 4.0≦A≦7.5.
    This permanent magnet may contain one or more additional elements selected from Nb, W, V, Ta and Mo. This permanent magnet has high coercive force and Curie temperature and thus highly improved thermal stability.





    Search report