RARE-EARTH REGENERATOR MATERIAL PARTICLES, AND GROUP OF RARE-EARTH REGENERATOR MATERIAL PARTICLES, REFRIGERATOR AND MEASURING APPARATUS USING THE SAME, AND METHOD FOR MANUFACTURING THE SAME

• US 20120157320A1
• Filed: 08/23/2010
• Published: 06/21/2012
• Est. Priority Date: 08/25/2009
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Materials Company Limited (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation), Toshiba Materials Company Limited (Toshiba Corporation)
• Inventors: Yamada, Katsuhiko, Fuse, Keiichi
• Granted Patent: US 9,556,374 B2
• Time in Patent Office: Days
• US Class Current: 505/162
• CPC Class Codes: B22F 9/08 by casting, e.g. through sieves or in water, by atomising or spraying using electric discharge B22F9/14
• CPC Class Codes: B22F 9/10 using centrifugal force
• CPC Class Codes: B23P 15/26 heat exchangers or the like making heat exchangers by methods covered by other subclasses B21D53/02
• CPC Class Codes: C09K 5/041 for compression-type refrigeration systems
• CPC Class Codes: C09K 5/08 Materials not undergoing a change of physical state when used C09K5/16, C09K5/20 take precedence
• CPC Class Codes: C09K 5/14 Solid materials, e.g. powdery or granular
• CPC Class Codes: C22C 2202/02 Magnetic
• CPC Class Codes: F25B 2309/003 characterised by construction or composition of the regenerator
• CPC Class Codes: F25B 2309/1415 Pulse-tube cycles characterised by regenerator details
• CPC Class Codes: F25B 9/14 characterised by the cycle used, e.g. Stirling cycle
• CPC Class Codes: F25B 9/145 pulse-tube cycle
• CPC Class Codes: G01R 33/3804 Additional hardware for cooling or heating of the magnet assembly, for housing a cooled or heated part of the magnet assembly or for temperature control of the magnet assembly
• CPC Class Codes: G01R 33/3815 with superconducting coils, e.g. power supply therefor
• CPC Class Codes: H01F 1/015 Metals or alloys
• CPC Class Codes: Y10T 428/12014 having metal particles

Abstract

Provided is a group of rare-earth regenerator material particles having an average particle size of 0.01 to 3 mm, wherein the proportion of particles having a ratio of a long diameter to a short diameter of 2 or less is 90% or more by number, and the proportion of particles having a depressed portion having a length of 1/10 to ½ of a circumferential length on a particle surface is 30% or more by number. By forming the depressed portion on the surface of the regenerator material particles, it is possible to increase permeability of an operating medium gas and a contact surface area with the operating medium gas.

Claims

1. Regenerator material particles, comprising a rare-earth metal and having an average particle size of 0.01 to 3 mm,

wherein a proportion of particles having a ratio of a long diameter to a short diameter of 2 or less is 90% or more by number, and

a proportion of particles having a depressed portion having a length of 1/10 to ½

of a particle circumferential length on a particle surface is 30% or more by number.

2. The particles of claim 1, wherein the depressed portion has a depth of 1/10 or less of a particle diameter.

3. The particles of claim 1, comprising at least one selected from the group consisting of Nd, Er₃Ni, and HoCu₂.

4. A refrigerator comprising a regenerator container comprising the particles of claim 1.

5. The refrigerator of claim 4, wherein the regenerator container comprises two or more stages comprising regenerator material-filled zones through a mesh material.

6. A measuring apparatus comprising a superconducting magnet comprising the refrigerator of claim 4.

7. The measuring apparatus of claim 6, which is at least one apparatus selected from the group consisting of an MRI and an NMR.

18. The particles of claim 1, comprising Nd.

19. The particles of claim 1, comprising Er₃Ni.

20. The particles of claim 1, comprising HoCu₂.

8. A method for manufacturing regenerator material particles comprising a rare-earth metal, the method comprising:

(a) heating a metal comprising a rare-earth element, to obtain a molten metal;

(b) supplying the molten metal to a rotary disk having a rotating velocity of 7000 to 11000 rpm in a chamber under an argon atmosphere, to obtain a molten metal having a granular form; and

(c) rapidly cooling the molten metal having a granular form, to obtain the regenerator particles.

9. The method of claim 8, wherein the molten metal is supplied through a jetting hole having a diameter of 0.05 to 2 mm.

10. The method of claim 8, wherein the rotary disk comprises a ceramic.

11. The method of claim 8, further comprising, prior to (b):

preliminarily heating the rotary disk to a temperature of 800°

C. or more.

12. A method for manufacturing regenerator material particles comprising a rare-earth metal, the method comprising:

(a) heating a metal comprising a rare-earth element, to obtain a molten metal;

(b) jetting the molten metal from a rotary nozzle having a rotating velocity of 7000 to 11000 rpm in a chamber under an argon atmosphere, to obtain a molten metal having a granular form; and

(c) rapidly cooling the molten metal having a granular form, to obtain the regenerator particles.

13. The method of claim 12, wherein a diameter of a jetting hole in the rotary nozzle is 0.05 to 2 mm.

14. The method of claim 12, further comprising, prior to (b):

preliminarily heating the rotary nozzle to a temperature of 800°

C. or more.

15. Rare-earth regenerator material particles, having:

a particle size of 0.01 to 3 mm;

a ratio of a long diameter to a short diameter of 2 or less; and

a depressed portion having a length of 1/10 to ½

of a circumferential length on a particle surface.

16. The particles of claim 15, wherein the depressed portion has a depth of 1/10 or less of a particle diameter.

17. The particles of claim 15, comprising at least one selected from the group consisting of Nd, Er₃Ni, and HoCu₂.