Method of Producing Sintered Magnets with Controlled Structures and Composition Distribution

Inactive Publication Date: 2013-10-10
GM GLOBAL TECH OPERATIONS LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The patent text describes a method for making a rare-earth magnet using a special alloy powder made of neodymium, iron, and boron. This powder is shaped and exposed to microwave radiation to create a sintered magnet. The technical effect of this method is to provide a more efficient and effective way to make rare-earth magnets, which are important for various applications such as electric motors and magnetic resonance imaging (MRI) machines.

Problems solved by technology

However, Dy and Tb are very rare and expensive.
The price of Dy has increased sharply in recent times. Tb, which is needed if higher magnetic properties are required than Dy can provide, is much more expensive than even Dy.
Dy or Tb (or their alloys) coated Nd—Fe—B powders are used to make the magnet, which results in a non-uniform distribution of Dy or Tb in the magnet microscopically.

Method used

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  • Method of Producing Sintered Magnets with Controlled Structures and Composition Distribution
  • Method of Producing Sintered Magnets with Controlled Structures and Composition Distribution
  • Method of Producing Sintered Magnets with Controlled Structures and Composition Distribution

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Embodiment Construction

[0015]Reference will now be made in detail to presently preferred compositions, embodiments and methods of the present invention, which constitute the best modes of practicing the invention presently known to the inventors. The Figures are not necessarily to scale. However, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for any aspect of the invention and / or as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0016]Except in the examples, or where otherwise expressly indicated, all numerical quantities in this description indicating amounts of material or conditions of reaction and / or use are to be understood as modified by the word “about” in describing the broadest scope of the invention. Practice within the nume...

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Abstract

A method of making a permanent magnet includes a step of providing an alloy powder comprising at least one rare earth element. The alloy powder is shaped and then exposed to microwave radiation or a pulsed electric current to form a sintered magnet.

Description

FIELD OF THE INVENTION[0001]In at least one aspect, the present invention relates to methods of making permanent magnets.BACKGROUND[0002]Permanent magnets (PMs) are used in a variety of devices, including traction electric motors for hybrid and electric vehicles. Sintered neodymium-iron-boron (Nd—Fe—B) permanent magnets have very good magnetic properties at low temperatures. However, due to the low Curie temperature of the Nd2Fe14B phase in Nd—Fe—B permanent magnets, the magnetic remanence and intrinsic coercivity decrease rapidly with increased temperature. It is known that the substitution of Dy for Nd or Fe in Nd—Fe—B magnets results in increases of the anisotropic field and the intrinsic coercivity, and a decrease of the saturation magnetization (C. S. Herget, Metal, Poed. Rep. V. 42, P. 438 (1987); W. Rodewald, J. Less-Common Met., V111, P77 (1985); and D. Plusa, J. J. Wystocki, Less-Common Met. V. 133, P. 231 (1987)). It is a common practice to add the heavy RE metals such as ...

Claims

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Application Information

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IPC IPC(8): B22F1/00B22F3/12
CPCC22C33/02B22F2999/00C22C2202/02H01F1/0577H01F1/0573H01F41/0293B22F3/10B22F3/105B22F2003/1054H01F41/0266
InventorWANG, YUCONG
OwnerGM GLOBAL TECH OPERATIONS LLC