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Alloys for magnetic shielding

Due to their high permeability 80 % NiFe alloys (MUMETALL®) are the first choice whenever high shielding factors are needed. In case of higher field strengths 50 % NiFe alloys (PERMENORM®) offer a higher saturation flux density and/or are a cost effective option. To shield very high magnetic fields
50 % CoFe alloys (VACOFLUX® 50) are available.

For simpler shielding problems pure iron or some magnetic steels can be used but should be magnetically annealed.

CRYOPERM® is a special composition which enables after suitable magnetic annealing similar magnetic properties than MUMETALL® at room temperature.

Typical magnetic properties after annealing
Alloy Composition µ4 (50 Hz) HC [A/m] BS [T] TCurie [°C] Thermal expansion [10-6/K] (20...100°C) Specific electrical resistance [µOm] Density [g/cm³]
VITROVAC® 6025 I50X 80 % Co 20000 1 0,57 200 12 1,35 7,7
VACOPERM® 100 80 % NiFe 90000 2 0,78 400 13,5 0,6 8,7
MUMETALL® 80 % NiFe 50000 3 0,80 400 13,5 0,6 8,7
PERMENORM® 5000 H2 50 % NiFe 12000 10 1,55 440 10 0,45 8,25
VACOFLUX® 50 (strip) 50 % CoFe 1000 90 2,35 950 9,5 0,35 8,12
VACOFLUX® 50 (massive) 50 % CoFe 1000 (static) 200 2,35 950 9,5 0,35 8,12
Soft iron 99,9 % Fe 1000 (static) 80 2,15 770   0,107 7,86
CRYOPERM® 10 80 % NiFe * * * *   0,35 8,7
TRAFOPERM® N3 3 % SiFe 1000 (static) 25 2,03 750 12 0,4 7,65
µ4: µr at 0,4 A/m