EMI Magnetic Shielding Alloys Supplier | Custom Fabricated Shields | MuMETAL® Science Research and Education
WORLDWIDE MANUFACTURER and  DISTRIBUTOR Since 1941   Magnetic Shield Corporation, a division of Perfection Mica Company, is the premier supplier of custom magnetic shielding alloys and custom Built shields.

FOR MuMETAl® & co-netic® alloys  

MuMETAL® Sheet
 Stress Annealed
Annealed Foil

MuMETAL® Is Known Worldwide
MuMETAL® alloy recognized as the "industry standard" provides very high magnetic permeability and the highest possible attenuation available in sheet and foil forms. Co-NETIC® and NETIC® specialty alloys are also widely specified by OEM, Design, and Electrical Engineers because each of these material types are all field proven scientifically to be the materials of choice for low-frequency magnetic shielding. Our proprietary brand, MuMETAL® meets MILSPEC 14411C,
composition 1.
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Perfection annealing is a heat treatment process that produces the highest permeability shielding. Typically, atmospherically controlled annealing is required after stamping, machining, bending, rolling or welding to provide maximum shielding performance.
Stress Annealed | Final Annealed (Perfection Annealed)
MuMETAL® is typically stocked in a stress annealed state to allow further fabrication, stamping, severe forming or welding. During fabrication, a material’s grain structure is weakened. After final fabrication processes are completed, grain structure is then modified by controlled atmospheric annealing to relieve stress in the material, resulting in larger grain structure, softer temper, and ultimate shielding performance. Although MuMETAL® is available in many forms, most shields are fabricated from foil or sheet stock.

Learn more - Manufacturing, Tooling, and Design

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Perfection Anneal - Optimum Magnetic Properties
After fabricating a magnetic shield, final annealing is generally required to increase grain structure, which improves shielding efficiency. Final anneal is a critical process step and extra care must be taken to avoid dropping or denting as shock may weaken an annealed shield's grain structure. MuMETAL® magnetic shields are Perfection Annealed (fully annealed in a controlled hydrogen atmosphere) to Magnetic Shield Corporation's exacting standards. Optimum magnetic properties are obtained by annealing at a temperature of 1950-2050°F [about 1120°C], and cooling at a consistent rate which is critical to maintaining grain structure and part dimensions. To insure your shield is annealed properly, we can measure attenuation (a shield's ability to absorb magnetic energy) in our ISO 9001:2008 certified Quality Control Lab using one of our Helmholtz Coils. Fully annealed MuMETAL® offers attenuation properties that are considered the best available for most applications worldwide.

What are the manufacturing and design considerations
for fabricating magnetic shielding?

MuMETAL® Brochure

Highest efficiency
magnetic shielding
Magnetic Shield Corp. Brochure

Magnetic Shield Corporation
Leading the way since 1941

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