Transformation enabled nitride magnets absent rare earths and a process of making the same
AssigneeCase Western Reserve University
InventorDavid Matthiesen
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Abstract
A process for producing an ordered martensitic iron nitride powder that is suitable for use as a permanent magnetic material is provided. The process includes fabricating an iron alloy powder having a desired composition and uniformity; nitriding the iron alloy powder by contacting the material with a nitrogen source in a fluidized bed reactor to produce a nitride iron powder; transforming the nitride iron powder to a disordered martensitic phase; annealing the disordered martensitic phase to an ordered martensitic phase; and separating the ordered martensitic phase from the iron nitride powder to yield an ordered martensitic iron nitride powder.
Claims24
A material suitable for forming a martensitic iron-based alloy nitride, the material comprising a single-phase γ-austenite iron-based alloy nitride, wherein the single-phase γ-austenite iron-based alloy nitride has an alloy composition that enables a greater solubility of nitrogen in the single-phase γ-austenite compared to that of elemental iron.
A material suitable for forming an ordered α″-martensitic phase iron-based alloy nitride permanent magnet, the material comprising a single-phase γ-austenite iron-based alloy nitride, wherein the single-phase γ-austenite iron-based alloy nitride has an alloy composition comprising:
- nitrogen in the range from greater than 10.3 at. % to 11.1 at. %;
- and
- an alloying element selected from the group consisting of:
- chromium, aluminum, and manganese.
A permanent magnet comprising an ordered α″-martensitic phase iron-based alloy nitride having a composition (Fe,M)16N2, wherein M is an alloying element selected from the group consisting of:
- chromium, aluminum, and manganese.
Dependencies are inferred from the claim text.