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What is mumetal ?

It's a high magnetic permeability alloy composed of 80 % Nickel, 15 % iron, 5 % molybdenum, traces of Si Mn and C.
Physical properties :

• density : 8.7
• low corrosion in normal ambient conditions

Mumetal is worked like a stainless steel.

What is a magnetic shield ?

It is a protection against electromagnetic waves, which enables the ambient electromagnetic field to be mitigated within a given volume.

What is the extent of shielding ( frequency and power) ?

Any frequency can be shielded with a range of techniques. For low frequencies, use is made of high permeability materials ; for higher frequencies, low resistivity materials are used.
For very high frequencies (Giga hertz), paint-coating, plastics or other materials are more suitable.
For power, there is not necessarily any limit. It all depends on the objective aimed at.

Are high-tension lines dangerous for health ?

Maybe but nothing has officially been proved.

Why does a heat treatment need to be done for mumetal, supra, pure irons ?

Heat treatment is used to rearrange the crystal structure after plastic deformation.
It also enables the grain size, therefore the Bloch walls, to be enlarged.
After the treatment the field lines circulate better inside the materials.

At what value should you start shielding ?

There are no typical values. You should shield when the disturbances caused by electromagnetic fields become a concern.

Can a shield be thermally retreated ?

Yes.
It may be necessary when the shield has sustained shocks or when there is a doubt about its effectiveness.
In all cases, consult us before taking a decision .

Is a mumetal shield effective against mobile telephone waves ?

No. Mumetal is not effective against this type of wave whose frequencies are too high.

Are there works on electromagnetism ?

Yes, lots!!!!
But it's not our business to advise on them .

Receiving or transmitting shield ?

Both. Either you don't want a sensitive part to be disturbed or you don't want a part to disturb.

Where is the low frequency located ?

Between 0 and 100 kHertz.

Do you make shielded chambers ?

Yes. We design, fabricate and fit them.

Do you do finite element simulations ?

We subcontract this operation, which is quite expensive, when our traditional methods are no longer enough.
In nearly all cases, simulation is not needed.

Do you make prototypes ?

Yes. It is routine in our type of activity.

Do you make customer calls to take readings ?

Yes. We make calls when we consider it necessary or on specific request.

Does the shielding effect disappear with time ?

No. Except if the shield has sustained shocks or plastic deformation.

Do you guarantee a result ?

Yes if reasonably possible. We monitor mitigations with our Helmholtz coil or with Gauss meters.

Can I buy Mumetal and make my shield myself ?

You can, but make sure you know the rules for designing and dimensioning the shield.
Also remember that the shield has to be treated at more than 1000 degrees and that the fabrication has to be done accordingly .

Does aluminium foil stop electromagnetic fields ?

Only the electric component.
Generally, it is the magnetic component that is a concern.

What geometrical tolerance are you capable of working to ?

A tenth of a millimeter. Don't forget we're working with fine sheet metal.