Magnetic sintered composite material

• US 5,350,628 A
• Filed: 11/19/1992
• Issued: 09/27/1994
• Est. Priority Date: 06/09/1989
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Hirota, Ken, Sugaya, Yasuhiro, Inoue, Osamu, Satomi, Mitsuo, Kugimiya, Koichi
• Primary Examiner(s): Resan, Stevan A.
• Application Number:
  US07/978,564
• Time in Patent Office: 677 Days
• Field of Search: 428/402, 428/403, 428/404, 428/693, 428/698, 428/900, 428/307.3, 148/307, 148/310, 335/302, 75/232, 75/233, 75/234, 75/235, 360/110, 360/125, 336/110
• US Class Current: 428/307.3
• CPC Class Codes: G11B 5/133 with cores composed of particles, e.g. with dust cores, with ferrite cores with cores composed of isolated magnetic particles in thin films G11B5/31
• CPC Class Codes: G11B 5/193 the pole pieces being ferrite or other magnetic particles G11B5/1871 takes precedence; in thin film G11B5/31
• CPC Class Codes: H01F 1/083 in a bonding agent
• CPC Class Codes: H01F 1/24 the particles being insulated
• CPC Class Codes: Y10S 428/90 Magnetic feature
• CPC Class Codes: Y10T 428/115 Magnetic layer composition
• CPC Class Codes: Y10T 428/249956 Void-containing component is inorganic
• CPC Class Codes: Y10T 428/2991 Coated

Abstract

A magnetic material is provided which includes a discrete phase including grains made of a first substance which comprises a magnetic metal; and a continuous phase including a thin coating film made of a second substance which comprises a dielectric or insulating substance. The thin coating film is formed on the surface of the grains and has a mean thickness smaller than the mean particle size of the grains. The grains are separated substantially from each other by the thin coating film.

Claims

1. A magnetic sintered composite material comprising:

a discrete phase including grains made of a first substance which comprises a magnetic metal or alloy thereof; and

a continuous phase consisting essentially of a dielectric thin coating film of an oxide or nitride of a metal or alloy, said thin coating film being formed on the surface of said grains and having a mean thickness smaller than the mean particle size of said grains,

wherein said grains are separated substantially from each other by said thin coating film, said magnetic sintered composite material having an electrical resistivity on the order of at least 10⁶ times that of said magnetic metal or alloy thereof, said first substance being an alloy selected from the group consisting of an iron-aluminum, an iron-silicon, an iron-nickel, an iron-nickel-molybdenum, and an iron-silicon-aluminum-cobalt.

2. A magnetic sintered composite material according to claim 1, wherein said first substance contains an alloy selected from the group consisting of an iron-aluminum, an iron-silicon, an iron-nickel, an iron-nickel-molybdenum, and an iron-silicon-aluminum-cobalt, said grains made of the first substance have a mean particle size ensuring the formation of a single magnetic domain structure, and the axes of easy magnetization of said grains coincide with each other.

3. A magnetic sintered composite material according to claim 1, wherein said thin coating film is formed from a member of the group consisting of aluminum oxide, aluminum nitride, magnesium oxide, manganese-zinc ferrites and nickel-zinc ferrites.

4. A magnetic sintered composite material according to claim 1, having a porosity of 5% or less.

5. A magnetic sintered composite material according to claim 4, having a porosity of 0.5% or less.

6. A magnetic sintered composite material according to claim 1, wherein said grains made of the first substance have a platelet shape.

7. A magnetic sintered composite material according to claim 1, wherein said grains made of the first substance have a needlelike shape.

8. A magnetic sintered composite material according to claim 6, having a porosity of 0.1% or less.

9. A magnetic sintered composite material according to claim 6, having a microstructure in which said grains made of the first substance are oriented.

10. A magnetic sintered composite material according to claim 6, wherein said platelet grains have an axis of easy magnetization along their major axes.

11. A magnetic head comprising a magnetic core which is made of a magnetic sintered composite material of claim 6, wherein said grains oriented in the magnetic core have their flat surface perpendicular to a running direction of magnetic media.

12. A magnetic head according to claim 11, wherein said platelet grains have an axis of easy magnetization along their major axes.

13. A magnetic sintered composite material according to claim 1, wherein said magnetic material is formed as a magnetic head.

14. A magnetic sintered composite material according to claim 1, wherein said magnetic material is formed as a core of a magnetic transformer.

15. A magnetic sintered composite material according to claim 1, wherein said magnetic material is formed as a hard magnet.