I am given to know that soft iron is used as temporary electromagnet since it has high permeability i.e. the ability to align its domains corresponding to the electric field around it, however has a low retentivity. On the contrary, steel is used as a weak, albeit permanent magnet since it has large retentivity and low permeability. I want to know whether- by means of optimization- soft iron can be made to retain the MEEC for a prolonged period of time and/or steel composition can be modified in order to able it to align its domains with greater ease and thereby make a stronger permanent magnet.

  • $\begingroup$ By MEEC, of course I mean Magnetic Effect of Electric Current. $\endgroup$
    – Graviton
    Commented May 30, 2012 at 16:19
  • $\begingroup$ Most high grade steels tend to avoid these specific elements that aid in MEEC, They result in a weaker formation of the grain flow. $\endgroup$
    – Argus
    Commented May 31, 2012 at 5:11

1 Answer 1


The short answer is, yes, it can be modified.

The coercitive field depends a lot on the microscopic details, such as grain boundaries and the material composition. For strong changes in the magnetic properties you need additional elements, such as Nb, Co or Ni. Additionally the details of the manufacturing process can influence the magnetic properties as well (sintering parameters, annealing).

A nice introduction into different materials and optimization possibilities can be downloaded from Vacuumschmelze, a large manufacturer of permanent magnets.

  • $\begingroup$ What do Nb, Co and Ni affect? Retentivity or Permeability. $\endgroup$
    – Graviton
    Commented May 30, 2012 at 16:35
  • $\begingroup$ @argentocyanide: both. $\endgroup$
    – Alexander
    Commented May 30, 2012 at 16:36
  • $\begingroup$ And what are they added to? Iron or Steel. Because steel seems to have a pretty thorough comp., which makes it less effective as a metal alloy when Cobalt, etc. are added to it. $\endgroup$
    – Graviton
    Commented May 30, 2012 at 16:38
  • $\begingroup$ @argentocyanide: Usually Iron, as materials optimized for their magnetic properties are not exposed to a lot of mechanical stress. But there is no reason why you can't create a steel alloy with these elements as well. $\endgroup$
    – Alexander
    Commented May 30, 2012 at 19:44

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