Magnet particles and magnet molding using same

Patent metadata

Field	Value
Publication number	US-10325705-B2
Application number	US-201515750238-A
Country	US
Kind code	B2
Filing date	Aug 24, 2015
Priority date	Aug 24, 2015
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

A bond magnet molding is provided that contains coated magnetic particles having at least two layers of an oxide layer of 1-20 nm on a surface of magnetic particles and an organic layer of 1-100 nm on an outer side of the oxide layer. The bond magnet molding preferably includes a Zn alloy as a binder. The Zn alloy has a strain rate sensitivity exponent (m value) of not less than 0.3 and an elongation at break of not less than 50%. The magnet particles have a nitrogen compound containing Sm and Fe that are solidified using the binder at a temperature not higher than a molding temperature.

First claim

The invention claimed is:

1. Coated magnetic particles comprising:
magnetic particles comprising a rare earth element;
at least two layers of an oxide layer of 1-20 nm on a surface of the magnetic particles; and
an organic layer of 1-100 nm on an outer side of the oxide layer.

2. Magnetic particles recited in claim 1 , wherein
the organic layer is formed in a mixed solution of a fatty acid ester and an alcohol.

3. A metal bond magnet molding produced by molding with the coated magnetic particles according to claim 1 .

4. The metal bond magnet molding as recited in claim 3 , wherein
the molding method includes die molding.

5. The metal bond magnet molding as recited in claim 3 , wherein
the metal bond magnet molding has a relative density of at least 50%.

6. The metal bond magnet molding as recited in claim 3 , wherein
the magnetic particles have a boundary layer inside the molding having a thickness of 1-20 nm and including at least one of an intermittent oxide, carbide, organic material, void, or a composite thereof.

7. The metal bond magnet molding as recited in claim 3 , wherein
the magnetic particles are Sm—Fe—N compounds.

8. The metal bond magnet molding as recited in claim 7 , wherein
the metal bond magnet molding is produced by mixing the coated magnetic particles and Zn particles blended as a metal binder to form a mixture and subjecting the mixture to solidification molding by die molding, and further subjecting to heat treatment.

9. The metal bond magnet molding as recited in claim 8 , wherein
a thickness of a densified region formed by a reaction product of Zn and Fe produced around the Zn binder is 5μm or less in the magnet molding.

10. The metal bond magnet molding as recited in claim 8 , wherein
an amount of the Zn particles is 1-15 wt % relative to a total weight of the coated magnetic particles and the Zn particles.

11. The metal bond magnet molding as recited in claim 3 , wherein
the metal bond magnet molding has a relative density of at least 80%.

12. An electromagnetic device using the metal bond magnet molding as recited in claim 3 .

13. The electromagnetic device recited in claim 12 , wherein
the electromagnetic device is at least one of a vehicle-mounted sensor, an on-board motor, an actuator, and a voltage conversion device.

Assignees

• Nissan Motor

Inventors

• Kawashita Yoshio
• Arai Masaya
• Murakami Ryou
• Fujikawa Shinichirou

Classifications

• H01F1/083

  in a bonding agent · CPC title

• H01F41/0266

  Moulding; Pressing (H01F41/0273 takes precedence; hard magnetic particles H01F1/06, H01F1/11) · CPC title

• H01F1/0558

  bonded together · CPC title

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title