Net shape processing of permanent magnet by field assisted sintering
AssigneeFord Global Technologies, LLC
InventorsWanfeng Li, Michael W. Degner
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Abstract
Magnets having various portions of different densities and resistivities are disclosed. In a refinement, the various portions may have the same composition but different physical structures. Unique dies may be used to during processing, such as during sintering to manufacture the magnets. The die may include conductive and non-conductive surfaces that contact the green magnetic powder mixture during sintering such that the electrical current applied to the magnetic powder mixture is managed by the conductive and non-conductive surfaces to provide unique and complex magnets. Methods of manufacturing the magnets with the dies such as field assisted sintering, i.e., spark plasma sintering, are also disclosed.
Claims16
A method of manufacturing a permanent magnet, the method comprising:
- exposing a magnetic powder to a magnetic field;
- contacting a first die having a first conductive surface portion and a first insulating surface portion with the magnetic powder at a first pressure;
- contacting a second die with the magnetic powder opposite the first die, the second die having a second conductive surface portion and a second insulating surface portion such that the second insulating surface portion is opposite the first insulating surface portion;
- and
- applying an electrical current to the magnetic powder through the first die such that the first conductive surface portion applies a greater electrical current density than the first insulating surface portion to form a sintered magnet having a first high-density portion adjacent the first conductive surface portion and between the first and second conductive surface portions, and a first low-density portion adjacent the first insulating surface portion and between the first and second insulating surface portions, wherein forming the first low-density portion includes forming a gap between the first and second insulating surface portions.
Dependencies are inferred from the claim text.