(19)
(11) EP 0 342 922 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
31.01.1990 Bulletin 1990/05

(43) Date of publication A2:
23.11.1989 Bulletin 1989/47

(21) Application number: 89304926.2

(22) Date of filing: 16.05.1989
(51) International Patent Classification (IPC)4: H01F 1/14, C22C 38/16, C21D 6/00
(84) Designated Contracting States:
DE FR GB

(30) Priority: 17.05.1988 JP 118335/88
30.11.1988 JP 300686/88

(71) Applicant: KABUSHIKI KAISHA TOSHIBA
Kawasaki-shi, Kanagawa-ken 210 (JP)

(72) Inventors:
  • Sawa, Takao c/o Toshiba Corporation
    Minato-ku Tokyo 105 (JP)
  • Okamura, Masami c/o Toshiba Corporation
    Minato-ku Tokyo 105 (JP)

(74) Representative: BATCHELLOR, KIRK & CO. 
2 Pear Tree Court Farringdon Road
London EC1R 0DS
London EC1R 0DS (GB)


(56) References cited: : 
   
       


    (54) Fe-based soft magnetic alloy and dust core made therefrom


    (57) Fe-based soft magnetic alloy having improved soft magnetic characteristics with high saturated magnetic flux density, characterized in having fine crystal grains and defined by formula (I)
    Fe100-a-b-cCuaMbYc      (I)
    wherein
    "M" is at least one element from:
    groups IVa, Va, VIa of the periodic table, Mn, Co, Ni, Al, and the Platinum group,
    "Y" is at least one of:
    Si, B, P, and C,
    and wherein a, b and c, in atomic % are defined thus:
    3 < a≦ 8
    0.1< b≦ 8
    3.1≦ a+b≦ 12
    15 ≦ c ≦ 28.
    A dust core made from an alloy powder having fine crystal grains is defined by formula (II)
    Fe100-a-b-c-d-eCuaM′bM˝cSidBe      (II)
    wherein
    "M′" is at least one element from:
    Groups IVa, Va, VIa of the periodic table;
    "M˝" is at least one element from:
    Mn, Co, Ni, Al, and the Platinum group;
    and wherein a, b, c, d and e, in atomic %, are defined thus
    3< a≦ 8
    0.1< b≦ 8
    0≦ c≦ 15
    8≦ d≦ 22
    3≦ e≦ 15
    15≦ d+e ≦ 28.







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