Most of electrical sensitive equipments for example transducers, sensors and detectors need security from the electromagnetic interference. Extensive interference is prevented by using a fine conductive metallic layer of mumetal, they fit for various frequency magnetic fields.

Mild frequency magnetic interference can be released from equipments for example switches, motors, power units, transformers etc that usually developed challenging EMI shielding issues. An accurate underlying circuitry is essential, magnetic shielding is needed and is usually attained by the use of such special ferromagnetic materials that have good magnetic permeability.

Alloys offering good magnetic permeability secure the sensitive equipments from the electrical noise developed by magnetic fields by altering the direction of magnetic field away from the security equipment.

In the same manner, the equipments that release low frequency magnetic fields can be separated by using the materials possessing good magnetic permeability.

In addition of good permeability, strength of magnetic field is also a crucial factor. Each metal has a magnetic saturation that describes the strength of magnetic that it can withstand. In the strong magnetic fields, the shields may become full, subsequent to which it is unable to offer required shielding. Most of materials selected for effective magnetic intensity applications offer good saturation, although larger saturation usually compromises with the absolute permeability that can be attained.

Shielding materials –magnetic characteristics and grain structure

The major application for shielding low frequency EMI is to utilize a good permeability magnetic shielding sheet metal or foil. The widely used shielding foil is MuMetal. For most of the alloy foils the magnetic shielding characteristics depend on retaining a good crystalline grain size in the material of about 100 micro-m or higher.

The special foils made from Mumetal are excellent in shielding electromagnetic interference. They are perfect to simply shield the shaped components.

As the super metal sheets or foils are made flat, materials that prevent forming operations, for example glassy amorphous alloys, they should be cut to shape and fabricated in flat surfaces to obtain the required component shielding. However these materials offer supreme shielding service, their distribution approach is a significant technique to shield the components.

Various mildly shielding materials can also be cut and fabricated to the desired shape. But their poor material quality is ineffective in offering the required shield by deformation of the material – damaging the material feature that produces the good permeability. To prevent the defects, a material annealed in the high temperature, is used to restore shielding efficiency. It shows a limitation for customers as the limitation for customers to combine the fabrication procedure with annealing.

An alternative is to use high magnetic permeability material, Mumetal wire that prevents the common drawbacks of the other materials including preventing the need of annealing of material. It is used frequently for enclosure for offering good strength and durability.

The specialty ferromagnetic foils and sheet metal are significant for the development of magnetic shield components for preventing low to high frequency electromagnetic shielding. It is a possible solution for the common shielding application requirements.