Manufacturing nd-fe-b magnets using hot pressing with reduced dysprosium or terbium
AssigneeGM Global Technology Operations LLC
InventorYucong Wang
Life of this patent
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Abstract
A method of making a magnetic material for a permanent magnet using hot-pressing or die-upset methods, or both, by combining two powders and optimizing grain boundary diffusion of Dy or Tb. The method can include making magnetic material for a permanent magnet using hot pressing using a core powder containing Nd, Fe and B and a surface powder containing Dy or Tb in metallic alloy form, combining the materials, forming a solid material in a shaped mold under a magnetic field in vacuum, heating the solid material, hot pressing it to form a magnetic material in a die, heat treating it if necessary, and then cooling it.
Claims20
A method of making a magnetic material for a permanent magnet using hot pressing comprising:
- providing:
- a first material in the form of a core powder containing Nd, Fe and B;
- a second material in the form of a surface powder containing Dy, Tb, or both in metallic alloy form;
- combining the first material with the second material so that a coated, composite-like material is formed with a non-uniform distribution of the Dy or the Tb that makes up the second material;
- forming the magnetic material in a shaped mold under a magnetic field in a vacuum;
- heating the magnetic material from a first range of about 5° C. to about 35° C. to a second range of about 500° C. to about 850° C.;
- hot pressing the magnetic material in a die;
- and
- cooling the magnetic material in the vacuum under inert atmosphere for from about 1 to about 5 hours.
A method of making a magnetic material for a permanent magnet using die-upsetting comprising:
- providing:
- a first material in the form of a core powder containing Nd, Fe and B;
- a second material in the form of a surface powder containing Dy, Tb, or both in metallic alloy form;
- combining the first material with the second material so that a coated, composite-like material is formed with a non-uniform distribution of the Dy or the Tb that makes up the second material;
- forming a solid material in a shaped mold;
- heating the solid material from a first range of about 5° C. to about 35° C. to a second range of about 550° C. to about 900° C.;
- deforming the solid material from about 20 to about 80 percent to form a magnetic material;
- and
- cooling the magnetic material in the vacuum under inert atmosphere for from about 1 to about 5 hours.
A method of making a magnetic material for a permanent magnet using hot pressing and die-upsetting comprising:
- providing:
- a first material in the form of a core powder containing Nd, Fe and B;
- a second material in the form of a surface powder containing Dy in metallic alloy form;
- combining the first material with the second material so that a coated, composite-like material is formed with a non-uniform distribution of the Dy that makes up the second material;
- forming a solid material in a shaped mold;
- heating the solid material from a first range of about 5° C. to about 35° C. to a second range of about 500° C. to about 850° C.;
- hot pressing the solid material in a die;
- heating the solid material after the hot pressing to a third range of about 550° C. to about 900° C., wherein the heating is performed after the hot pressing;
- deforming the solid material from about 20 to about 80 percent to form a magnetic material;
- and
- cooling the magnetic material in the vacuum under inert atmosphere for from about 1 to about 5 hours.
Dependencies are inferred from the claim text.