Iron Chrome Cobalt magnets (FeCrCo)

Iron Chrome Cobalt magnets (FeCrCo) have similar properties to cast Alnico 5 but, unlike cast Alnico, the FeCrCo magnets are actually reasonably malleable. The FeCrCo magnet material is semi-hard magnetically and exists in bar, rod, wire and also as thin rolled strip. They are a replacement for CuNiFe magnetic material (CuNiFe is not commercially available anymore).

Adavantages & Disadvantages of Iron Chrome Cobalt magnets (FeCrCo)

Adavantages

  • Malleable – FeCrCo is easier to machine than Alnico
  • FeCrCo can be hot deformed
  • The maximum recommended operating temperature is typically around +400°C (752°F)
  • FeCrCo has a Hc varying typically from 50kA/m to 300kA/m. The value of Hc produced depends on the method of the final heat treatment (timescale, temperature and quench rate)
  • FeCrCo usually does not require any corrosion coating

Disadvantages

  • If the final heat treatment is not performed, the magnetic performance is very poor
  • The strips are usually thin. Thicker sheets and plate are not really possible
  • Easily demagnetized or remagnetized in a different direction

Typical applications for Iron Chrome Cobalt magnets (FeCrCo)

  •  Compasses
  • Hysteresis coupling applications e.g. a multi-pole permanent magnet rotor turning a FeCrCo disc by hysteresis

Example: A company wanted a customised needle for a compass they were designing. The needle could be produced to the shape, heat treated, painted and magnetised to their requirements.