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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:
| Material | Saturation | Permeability | |
| (Gauss) | µ Max | µ 40 | |
| Amumetal (80% Nickel) | 8,000 | 400,000 | 60,000 |
| Amunickel (48% Nickel) | 15,000 | 150,000 | 12,000 |
| *Cryoperm 10 | 9,000 | 250,000 | 65,000 |
| Ultra Low Carbon Steel | 22,000 | 4,000 | 1,000 |
* 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.
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
| Composition | Thickness | Max. Width |
| Amumetal | .002" | 24.00" |
| Amumetal | .004" | 16.00" |
| Amumetal | .006" | 16.00" |
| Amumetal | .010" | 16.00" |
| Amumetal | .010" | 16.00" |
| ULCS | .004" | 24.00" |
| ULCS | .006" | 24.00" |
| ULCS | .010" | 24.00" |