Method for making wound magnetic core

• US 5,083,366 A
• Filed: 08/01/1991
• Issued: 01/28/1992
• Est. Priority Date: 02/02/1989
• Status: Expired due to Term

• Current Assignee: Hitachi Metals (Thailand) Ltd.
• Original Assignee: Hitachi Metals (Thailand) Ltd.
• Inventors: Arakawa, Shunsuke, Hirao, Noriyoshi, Yamauchi, Kiyotaka
• Primary Examiner(s): Hall, Carl E.
• Application Number:
  US07/739,096
• Time in Patent Office: 180 Days
• Field of Search: 29/605, 336/213, 336/219, 148/306
• US Class Current: 29/605
• CPC Class Codes: H01F 1/15383 Applying coatings thereon H01F1/15366 takes precedence
• CPC Class Codes: H01F 3/04 made from strips or ribbons
• CPC Class Codes: H01F 41/0226 from amorphous ribbons
• CPC Class Codes: Y10T 29/49071 by winding or coiling

Abstract

A wound magnetic core constituted by (a) a thin ribbon made of a fine crystalline, soft magnetic Fe-base alloy having the composition represented by the general formula:

(Fe.sub.1-a M.sub.a).sub.100-x-y-z-α Cu.sub.x Si.sub.y B.sub.z

M'"'"'.sub.α

wherein M is Co and/or Ni, M'"'"' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, and a, x, y, z and α respectively satisfy 0≦a≦0.5, 0.1≦x≦3, 0≦y≦30, 0≦z≦25, 5≦y+z≦30 and 0.1≦α≦30, at least 50% of the alloy structure being occupied by fine crystal grains having an average grain size of 1000 Å or less; and (b) a heat-resistant insulating layer having a thickness of 0.5-5 μm formed on at least one surface of the thin ribbon, the heat-resistant insulating layer being made of a uniform mixture of 20-90 weight %, as SiO₂, of a silanol oligomer and 80-10 weight % of fine ceramic particles, which is subjected to a heat treatment to cross-link the silanol oligomer.

Claims

1. A method of producing a wound magnetic core constituted by (a) a thin ribbon made of a fine crystalline, soft magnetic Fe-base alloy having the composition represented by the general formula:

space="preserve" listing-type="equation">(Fe.sub.1-a M.sub.a).sub.100-x-y-z-α

Cu.sub.x Si.sub.y B.sub.z M'"'"'.sub.α

wherein M is Co and/or Ni, M'"'"' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, and a, x, y, z and α

respectively satisfy 0≦

a≦

0.5, 0.1≦

x≦

3, 0≦

y≦

30, 0≦

z≦

25, 5≦

y+z≦

30 and 0.1≦

α

≦

30, at least 50% of the alloy structure being occupied by fine crystal grains having an average grain size of 1000 Å

or less; and

(b) a heat-resistant insulating layer formed on at least one surface of said thin ribbon, comprising the steps of;

(a) applying to at least one surface of a thin ribbon made of an amorphous alloy having the same composition as above a dispersion containing 20-90 weight %, as SiO₂, of a silanol oligomer and 80-10 weight % of fine ceramic particles based on a solid component, in a thickness of 0.5-5 μ

m on a dry basis;

(b) winding said thin ribbon after drying; and

(c) subjecting the resulting wound magnetic core to a heat treatment at 450°

-700°

C. for 5 minutes-24 hours to finely crystallize said amorphous alloy and to cause the cross-linking of said silanol oligomer.

2. The method according to claim 1, wherein said silanol oligomer is a polymer of a hydrolyzate of a silicon alkoxide substantially having the structure represented by RSi(OR)₃, said silanol oligomer having an average molecular weight of 500-8000.

3. The method according to claim 1, wherein said fine ceramic particles are ceramic colloidal particles.

4. The method according to claim 3, wherein said ceramic colloidal particles are colloidal silica.

5. A method of producing a wound magnetic core constituted by (a) a thin ribbon made of a fine crystalline, soft magnetic Fe-base alloy having the composition represented by the general formula:

space="preserve" listing-type="equation">(Fe.sub.1-a M.sub.a).sub.100-x-y-z-α

-β

-γ

Cu.sub.x Si.sub.y B.sub.z M'"'"'.sub.α

M".sub.β

X.sub.γ

wherein M is Co and/or Ni, M'"'"' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, M" is at least one element selected from the group consisting of V, Cr, Mn, Al, elements in the platinum group, Sc, Y, rare earth elements, Au, Zn, Sn and Re, X is at least one element selected from the group consisting of C, Ge, P, Ga, Sb, In, Be and As, and a, x, y, z, α

, β and

γ

respectively satisfy 0≦

a≦

0.5, 0.1≦

x≦

3, 0≦

y≦

30, 0≦

z≦

25, 5≦

y+z≦

30, 0.1≦

α

≦

30, β

≦

10 and γ

≦

10, at least 50% of the alloy structure being occupied by fine crystal grains having an average grain size of 1000 Å

or less; and

(b) a heat-resistant insulating layer formed on at least one surface of said thin ribbon, comprising the steps of;

(a) applying to at least one surface of a thin ribbon made of an amorphous alloy having the same composition as above a dispersion containing 20-90 weight %, as SiO₂, of a silanol oligomer and 80-10 weight % of fine ceramic particles based on a solid component, in a thickness of 0.5-5 μ

m on a dry basis;

(b) winding said thin ribbon after drying; and

(c) subjecting the resulting wound magnetic core to a heat treatment at 450°

-700°

C. for 5 minutes-24 hours to finely crystallize said amorphous alloy and to cause the cross-linking of said silanol oligomer.

6. The method according to claim 5, wherein said silanol oligomer is a polymer of a hydrolyzate of a silicon alkoxide substantially having the structure represented by RSi(OR)₃, said silanol oligomer having an average molecular weight of 500-8000.

7. The method according to claim 5, wherein said fine ceramic particles are ceramic colloidal particles.

8. The method according to claim 7, wherein said ceramic colloidal particles are colloidal silica.