Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-15T01:46:33.659Z Has data issue: false hasContentIssue false
  • English
  • Français

Rapidly Solidified Neodymium-Iron-Boron Magnets

Published online by Cambridge University Press:  29 November 2013

J.J. Croat  and
J.F. Herbst
Get access

Extract

Permanent magnets have long occupied an important position in technology. Among the multitude of products using permanent magnets are televisions, telephones, computers, videocassette recorders, audio systems, household appliances, and perhaps surprisingly to many consumers, automobiles. Figure 1 illustrates the numerous magnet applications in a modern passenger vehicle. These applications include an array of dc electric motors such as the starter, heater and air conditioner blower, windshield wiper, window lift, door lock, and fuel pump motors. A fully equipped car can have more than 30 dc electric motors. Other uses include actuators, gauges, and sensors. In all these examples higher performance magnetic materials may afford the advantages of increased operating efficiency and reduction in size and weight.

One performance index or figure of merit for a permanent magnet is the energy product (BH)max, the maximum product of magnetic induction B and applied field H in the second quadrant of the B-H hysteresis curve. The so-called theoretical (BH)max, the highest energy product realizable in principle, is simply given by (4πMs)2/4, where Ms is the saturation magnetization. Progress in the development of technologically significant hard magnets has been monitored generally by improvements in (BH)max. For many years three types of materials were of commercial importance, namely, alnico, ferrite, and samarium-cobalt alloys based on either the SmCo5 or Sm2Co17 intermetallic compounds. Of these the Sm-Co magnets offer the largest energy products, on the order of 20 MGOe.

Type
Magnetism and Magnetic Materials
Information
MRS Bulletin , Volume 13 , Issue 6 , June 1988 , pp. 37 - 40
Copyright
Copyright © Materials Research Society 1988

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1.Croat, J.J., Herbst, J.F., Lee, R.W., and Pinkerton, F.E., Appl. Phys. Lett. 44 (1984) p. 148.CrossRefGoogle Scholar
2.Croat, J.J., Herbst, J.F., Lee, R.W., and Pinkerton, F.E., J. Appl. Phys. 55 (1984) p. 2078.CrossRefGoogle Scholar
3.Sagawa, M., Fujimura, S., Togawa, M., Yamamoto, H., and Matsuura, Y., J. Appl. Phys. 55 (1984) p. 2083; N.C. Koon and B.N. Das, J. Appl. Phys. 55 (1984) p. 2063; G.C. Hadjipanayis, R.C. Hazelton, and K.R. Lawless, J. Appl. Phys. 55 (1984) p. 2073; D.J. Sellmyer, A. Ahmed, G. Muench, and G. Hadjipanayis, J. Appl. Phys. 55 (1984) p. 2088.CrossRefGoogle Scholar
4.Herbst, J.F., Croat, J.J., Pinkerton, F.E., and Yelon, W.B., Phys. Rev. B 29 (1984) p. 4176.CrossRefGoogle Scholar
5.Herbst, J.F., Croat, J.J., and Yelon, W.B., J. Appl. Phys. 57 (1985) p. 4086.CrossRefGoogle Scholar
6.Lee, R.W., Appl. Phys. Lett. 46 (1985) p. 790.CrossRefGoogle Scholar
7. For a review, see Sagawa, M., Hirosawa, S., Yamamoto, H., Fujimura, S., and Matsuura, Y., Jpn. J. Appl. Phys. 26 (1987) p. 785.CrossRefGoogle Scholar
8.Shoemaker, C.B., Shoemaker, D.P., and Fruchart, R., Acta Cryst. 40 (1984) p. 1665.CrossRefGoogle Scholar
9.Givord, D., Li, H.S., and Moreau, J.M., Solid State Commun. 50 (1984) p. 497.CrossRefGoogle Scholar
10.Pearson, W.B., The Crystal Chemistry and Physics of Metals and Alloys (Wiley Interscience, New York, 1972) p. 643–661.Google Scholar
11.Gaskell, P.H., Nature 289 (1981) p. 474.CrossRefGoogle Scholar
12.Mishra, R.K., J. Magn. Magn. Mater. 54-57 (1986) p. 450.CrossRefGoogle Scholar
13.Mishra, R.K., in High Performance Permanent Magnet Materials, edited by Sankar, S. G., Herbst, J.F., and Koon, N.C. (Mater. Res. Soc. Symp. Proc. 96, Pittsburgh, PA, 1987) p. 8392.Google Scholar
14.Lee, R.W., Brewer, E.G., and Schaffel, N., IEEE Trans. Magn. 21 (1985) p. 1958.CrossRefGoogle Scholar