Journal of Materials Science

, Volume 6, Issue 2, pp 164–168 | Cite as

The magnetic and mechanical hardness of the intermetallic compounds SmCo5 and LaCo5

  • R. A. McCurrie
  • G. P. Carswell
  • J. B. O'Neill


The magnetisation, coercivity, HC, and remanence coercivity, HR, have been measured for the intermetallic compounds SmCo5 and LaCo5. The coercivities HC and HR for SmCo5 are very much greater than those for LaCo5. The differences in these parameters are much greater than would be expected from a simple theoretical model, so that they cannot be accounted for in terms of differences in the magnetocrystalline anisotropy constants. Since the specimens used for the magnetic measurements were produced by mechanical comminution, Knoop hardness measurements were made in an attempt to account for the magnetic behaviour in terms of the crystallographic damage and plastic deformation produced during the grinding process. The hardness results show that, within experimental error, the SmCo5 is very nearly isotropic, whereas the LaCo5 is very anisotropic on the {10¯10} planes with a Knoop hardness of 138 in the 〈0001〉 directions and 511 in the 〈12¯10〉. It is concluded that plastic deformation will occur more easily in LaCo5 and that this could, to some extent, explain the comparatively low coercivities.


Polymer Anisotropy Plastic Deformation Theoretical Model Experimental Error 
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Copyright information

© Chapman and Hall Ltd. 1971

Authors and Affiliations

  • R. A. McCurrie
    • 1
  • G. P. Carswell
    • 1
  • J. B. O'Neill
    • 2
  1. 1.School of Materials ScienceThe University of BradfordBradford 7UK
  2. 2.Rolls Royce and Associates LtdDerbyUK

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