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.
| 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 |
