Mu Metal

Key Features:

  1. Mu Metal offers high magnetic permeability
  2. Ideal magnetic shielding metal
  3. Low hysteresis losses
  4. Good formability and weldability
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About Mu Metal

Mu metal or Mu Metal shield is a soft ferromagnetic alloy therefore it doesn’t attain residual magnetism after the removal of external magnetizing force. It has very high initial and maximum permeability with nominal hysteresis loss. It offers small coercive force, nominal core losses and small remanence. To obtain the necessary magnetic functionality, Mu metal should be heat processed in a dry hydrogen condition furnace with a dew point below – 40oC at 1100oC to 1180oC for 2 to 4 hours. This heat processing improves the magnetic permeability by 40 folds.

Grain and magnetic domains size is improved by annealing of Mu metal. Although these extended grains are prone to vigorous shocks or additional mechanical processing and permeability will be lowered in these regions. It can be improved by reannealing. High permeability Mumetal offers a low reluctance path for magnetic flux leading for its use in magnetic shields in DC and AC current applications.

Industrial Nomenclatures: Mu metal, Mushield

Mu Metal Specifications: MIL-N-14411 C (MR), ASTM A-753-78

Mu Metal Applications

Electric transformer: Mu metal avoids contact to surrounding circuits.

Storage disks: In hard disks, mu metal prevents interfere of magnetic field to disk.

Mu metal is used in cathode ray tubes to avoid drift in magnetic fields due to redirected electron beam.

Other uses are in magnetic phonographs, magnetic resonance imaging devices, photomultipliers, vacuum containers and superconducting circuits.

Role of Mu metal in magnetic shielding

Extremely permeable Mu metal offers small reluctance path for magnetic field, finding its role in magnetic shields in static or nominally changing magnetic fields. Mu metal magnetic shielding gives a way to magnetic field lines enclosing the shielded region. Hence the suitable shape for shields is a closed chamber covering the shielded region. The suitability of this shielding depends on the permeability of a metal. Therefore mumetal shields are constructed of many enclosures one within other that significantly decreases the internal field. As mu metal saturates at small fields, the external layer in the multilevel shields is constructed of standard steel. With its larger saturation value, strong magnetic fields can be handled easily, control them to a suitably small level for effective shielding by internal mumetal layers.

Forms Produced

Mu Metal Wire Mu Metal Foil
Mu Metal Wire Mesh Mu Metal Sheet

Heanjia Super Metals, America offers all above forms of Mu Metal in all standard as well as custom specifications.