Sintered R2M17 magnet and method of fabricating a R2M17 magnet
AssigneeVacuumschmelze GmbH & Co. KG
InventorsKaan Üstüner, Matthias Katter, Christoph Brombacher
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Abstract
A sintered R2M17 magnet is provided that comprises at least 70 Vol % of a Sm2M17 phase, wherein R is at least one of the group consisting of Ce, La, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yt, Lu and Y, and M comprises Co, Fe, Cu and Zr. In an area of the R2M17 sintered magnet of 200 by 200 μm viewed in a Kerr micrograph, an areal proportion of demagnetised regions after application of an internal opposing field of 1200 kA/m is less than 5% or less than 2%.
Claims16
A method of fabricating a R2M17 alloy magnet, wherein R is at least one selected from the group consisting of Ce, La, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y and M comprises Co, Fe, Cu and Zr, wherein the R2M17 alloy comprises a phase diagram that comprises with decreasing temperature a first phase field, a second phase field and a third phase field, the phase diagram comprising a first boundary between the first phase field and the second phase field, the first phase field comprising a liquid phase and a solid R2M17 phase in equilibrium and the second phase field comprising a solid R2M17 majority phase with a phase fraction of larger than 95%, and a second boundary between the second phase field and the third phase field, the third phase field comprising a solid R2M17 phase and at least one further solid phase of differing composition in equilibrium, the method comprising:
- heat treating a body comprising an atomic ratio of 2R and 17M, wherein R is at least one selected from the group consisting of Ce, La, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, and M comprises Co, Fe, Cu and Zr, at a first temperature Ts above the first boundary and in the first phase field, followed by
- cooling the body through the first boundary, followed by
- heating up the body through the first boundary and heat treating the body at a temperature TAH between the first boundary and the first temperature Ts, followed by
- cooling the body through the first boundary and heat treating the body at a temperature below the first boundary.
A method of fabricating a R2M17 alloy magnet, wherein R is at least one selected from the group consisting of Ce, La, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, and M comprises Co, Fe, Cu and Zr, wherein the R2M17 alloy comprises a phase diagram that comprises with decreasing temperature a first phase field, a second phase field and a third phase field, the phase diagram comprising a first boundary between the first phase field and the second phase field, the first phase field comprising a liquid phase and a solid R2M17 phase in equilibrium and the second phase field comprising a solid R2M17 majority phase with a phase fraction of larger than 95%, and a second boundary between the second phase field and the third phase field, the third phase field comprising a solid R2M17 phase and at least one further solid phase of differing composition in equilibrium, the method comprising:
- heat treating a body comprising an atomic ratio of 2R and 17M, wherein R is at least one selected from the group consisting of Ce, La, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, and M comprises Co, Fe, Cu and Zr, at a first temperature Ts above the first boundary and in the first phase field, followed by
- cooling the body through the first boundary, followed by
- cooling the body through the second boundary and heat treating the body at a temperature TBH below the second boundary and above 900° C., followed by
- heating up the body through the second boundary and heat treating the body at a temperature between the second boundary and the first temperature Ts.
Dependencies are inferred from the claim text.