Magnetic saturation and ferrite magnets

[cmb]

Hi, I believe I understand the basics that permeability of materials is the function of change of flux density with magnetic field. So a non-magnetised material might have a high permeability (easy to increase the magnetic field) while a magnetised mass of the same material might well be close to air (already magnetised, so difficult to increase the magnetic field further).

Assuming that's right so far, I want to know what happens to, and in, ferrite magnets if they are exposed to a magnetic field that takes them above their magnetised flux density.

Presumably the relative permeability becomes 1 above the saturation of ferrite magnets, but I can't find any information when looking at specifications of ferrite magnets as to what their permeability is.

My questions are therefore;-
- Is that right so far?
- Are ferrites typically magnetised to just under their saturation, and therefore 'anything more' than their flux density means they have an effective permeability of 1? If not, can I tell by some other clever calculation (or secret stash of data sheets somewhere!?) what their flux density saturation level is?
- If that were to be the setup in a situation such that a piece of ferrite was placed in a magnetic circuit where the flux density exceeded its own nominal magnetised flux, does the magnetic energy of the ferrite 'add' linearly to the total magnetic energy in the magnetic circuit, or is it somehow 'overwhelmed' by the more powerful circuit flowing through it?

 

[Charles Link]

What you have written seems t be reasonably accurate, but the saturation is not sudden, except perhaps at extremely low temperatures. Thermal effects will cause the saturation and the decrease in permeability to occur somewhat gradually with applied field strength.

 

[cmb]

Thanks. To clarify I am talking about a static DC magnetic circuit.

I'm asking; what is the magnetic saturation of a ferrite magnet in a DC circuit whose magnetic flux exceeds the remanence of the permanent ferrite magnet? And does its magnetic energy add to the magnetic energy in the circuit, or is it somehow 'overwhelmed'?