The design of a quality magnetic shield begins with the proper material selection. As material consumption is a major component in determining a shield's cost and performance, it is necessary to understand the different shielding characteristics of our standard materials.

Material Characteristics
Magnetic shielding materials are chosen for their specific characteristics, usually in respect to permeability and saturation. As permeabilities increase in magnetic shielding materials, their saturation levels decrease. Therefore, the highest permeability alloys such as Amumetal have the lowest saturation values. Because a saturated shield is a poor attenuator, we must always select materials with adequate saturation characteristics to withstand the strength of a a given source field while providing the required attenuation of that field. The following are Amuneal's standard materials which provide the required material characteristics for different applications.

Most magnetic shields made today are constructed from high permeability materials such as Amumetal, an 80% nickel-iron alloy specially designed for magnetic shielding applications. This high nickel-content alloy conforms to both MIL-N-14411C, Composition 1 and ASTM A753-85, Type 4.

Amumetal is available in the following standard thicknesses in a maximum of 30.00" x 120.00" sheets.

.014" (0.356mm)
.020" (0.508mm)
.025" (0.635mm)
.030" (0.762mm)
.040" (1.016mm)
.050" (1.270mm)
.062" (1.575mm)
.125" (3.175mm)
Our standard thicknesses can be shipped to your site within 2-3 days of your request.

Amunickel
Amunickel is a medium permeability material providing greater saturation protection than Amumetal. Amunickel is a 48% nickel-iron alloy which conforms to MIL-N-14411C, Composition III, and should be used in applications where saturation is as great a concern as permeability. Amunickel is available in the same thicknesses as Amumetal but with a maximum width of 16.00".

Cryoperm 10
Cryoperm 10* is a high nickel content alloy which is specially processed to provide increasing permeabilities with decreasing temperatures. This material, depending on a discrete annealing cycle, is designed for use at either 4.2K or 77.3K, making Cryoperm 10 the ideal material for use in cryogenic applications. Cryoperm 10 is now available in three thicknesses (.020", .040" and .060") in sheets up to 10.23" wide.

Download Data Sheet for Cryoperm 10 and Custom Magnetic Shielding for Low Tempearture Applications

Download Cold Facts Article on Amuneal’s Cryoperm Magnetic Shielding

Ultra Low Carbon Steel (ULCS)
Amuneal's specially processed, ultra low carbon steel, has a relatively high permeability, compared to standard low carbon steels, and excellent saturation characteristics. This material is less brittle and easier to form than silicon steels allowing it to be easily fabricated and installed in large area shielding projects. ULCS can be used together with high permeability materials like Amumetal to create optimum shields for applications requiring both high saturation protection and high levels of attenuation.

The following table shows a comparison of the permeability and saturation values of these most commonly employed shielding materials:

* Information for Cryoperm 10 based on its use at Cryogenic temperatures. Cryoperm 10 is a registered trademark of Vacuumschmelze GmbH, Hanau, Germany.

Amuneal offers a complete line of shielding foils specially processed for applications where weight, space, complex geometry and performance are of primary concern. These foil materials are available in the identical chemical compositions and shielding characteristics as our Amumetal, Amunickel and Ultra low Carbon Steel (ULCS) materials.

Each of our shielding foils is available In a standard thickness of .002", .004", .006" and .010" and can be supplied in coil, strip or fabricated pieces in widths up, to 24.00". This material, like our sheet material, can be Hydrogen Annealed to insure optimum magnetic shielding characteristics.

These foils, because of their thickness can be cut with scissors and easily manipulated by hand. For applications where the amount of required shielding is unknown, or the geometry of the component to be shielded is very complex, our foils can be wrapped around these components until the interference is reduced to an acceptable level; each wrap of material will provide increased shielding performance. The chart to the left illustrates how shielding performance increases with each successive layer of foil.

In addition, Amuneal can laminate our foils with double-backed adhesives and dielectric insulators to products complete stamped components in small to very large volumes. These laminated foils are perfect for applications where a thin shield needs to be permanently affixed to a particular component or area.

Material Foil Standard Maximum