Temperature Compensation in the '2:17' type magnets

Camp, F. E.; Narasimhan, K.S.V.L.; Hurt, J. C.

doi:10.1109/tmag.1985.1064029

Cited by 14 publications

(2 citation statements)

References 6 publications

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“…A simplihas been investigated by various authors 6 . 7 . However, fying assumption was made that, at a given temperature, a generalized approach for identifying the alloys that magnetization is an additive property with the number can provide the needed temperature coefficient has not of rare earth atoms.…”

mentioning

confidence: 99%

Temperature Compensation in the '2:17' Type Magnets.

Narasimhan¹,

Camp²,

M.³

et al. 1986

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mentioning

confidence: 99%

Temperature Compensation in the '2:17' Type Magnets.

Narasimhan¹,

Camp²,

M.³

et al. 1986

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“…The concept of calculating 4TIM S in HRE-substituted rare earth permanent magnets was first proposed by F. E. Camp et al [44,45]. However, the approach they used for the calculation and their algorithms employed were not mentioned.…”

Section: X-ray Diffraction Results and Microstructurementioning

confidence: 99%

Development of New High Temperature and High Performance Permanent Magnet Materials

Liu¹,

Kuhl²

2000

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Permanent magnet materials capable of operating at high temperatures (>400°C) are required for advanced aerospace power systems. Prior to the UDRI AMPS team's successful program, the best available high temperature permanent magnets could not operate above 300°C. The problem for higher temperature operation has been that the strength of conventional magnets, as characterized by their intrinsic coercivity (MHC) drops sharply upon heating. The MHC of the best 2:17 rare earth-transition metal permanent magnets previously available drops from 20 to 30 kOe at room temperature to only 1 to 3 kOe at 500°C. This also results in nonlinear 2 nd -quadrant induction demagnetization curves (B curves) at temperatures above 200 to 300°C. A linear B curve is critical in all dynamic applications such as in generators and motors.The UDRI AMPS team's research advanced the maximum operating temperature of permanent magnets by as much as 250°C, to 550°C. The MHC of these new Sm-Co based magnets reached 9 kOe at 500°C (four to nine times higher than the current materials), with linear B curves to as high as 550°C (a 250 to 350°C increase). The temperature coefficients of MHC for the new magnets can be nearly constant and can range from a small negative value (-0.1%/°C) to near zero, or they may even be large and positive (up to +0.27%/°C). In comparison, the temperature coefficient of MHC is -0.36%/°C for conventional 2:17 and SmCo 5 magnets, and -0.9%/°C for Nd-Fe-B. In a conventional long-term aging test (500°C in air for 1,000 hours) the new magnets show a flux density loss less than one-third that of the best conventional 2:17 magnets. Using a dynamic characterization method (cycled between 0 and -6 kOe) at 400°C, the new magnet displays a dynamic energy product more than 20 times higher than the best conventional 2:17 magnet.The UDRI AMPS team also proposed a new theory of coercivity mechanisms in permanent magnet materials based on this breakthrough result. This new theory explains the variations in the temperature dependencies of coercivity and provides important guidance to the R&D of new magnetic materials. In addition, EEC has successfully commercialized the new high temperature permanent magnets. These advances represent a major breakthrough in high temperature permanent magnet materials. 1.3Temperature dependence of magnetic properties of the best 5 conventional high temperature Sm 2 (Co,Fe,Cu,Zr)i 7 magnet. 1.4Schematic illustration of importance of a linear B curve in a 6 dynamic condition. 2.1Saturation magnetization (47tM s ) of Sm-Co binary compounds vs. 9 Co content. 47tM s of LaCon is also given in the figure. 3.1High temperature intrinsic coercivity, M Hc, as a function of Fe 13 content, v, in Sm(Co ba iFe v Cu 0 .o9Zro.o3)7.5. 3.2Dependence of intrinsic coercivity of Sm(Co 0 .795Feo.o9Cuo.o9Zr 0 .o25)z 14 on z value at various temperatures. 3.3Temperature dependence of intrinsic coercivity for Sm(Co 0 .795Fe 0 .o9 " 15 Cuo.o9Zr 0 .o25)z from 300 to 600°C. 3.4Temperature dependence of intrinsic coerci...

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Recent Developments in High-Temperature Permanent Magnet Materials

Liu

Handbook of Advanced Magnetic Materials

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Temperature Compensation in the '2:17' type magnets

Cited by 14 publications

References 6 publications

Temperature Compensation in the '2:17' Type Magnets.

Temperature Compensation in the '2:17' Type Magnets.

Development of New High Temperature and High Performance Permanent Magnet Materials

Recent Developments in High-Temperature Permanent Magnet Materials

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