Magnetic saturation and ferrite magnets

In summary, the conversation discusses the permeability of materials and how it relates to their magnetization. It is noted that ferrite magnets have a saturation point where their permeability decreases and becomes 1. The questions posed are about the saturation point of ferrite magnets in a DC magnetic circuit and how their magnetic energy interacts with the circuit. The response clarifies that saturation is not sudden and can be affected by temperature.
  • #1
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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?
 
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  • #2
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.
 
  • #3
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'?
 

1. What is magnetic saturation?

Magnetic saturation is the point at which a magnetic material can no longer be magnetized, even with the application of a strong external magnetic field. This occurs when all of the magnetic domains within the material are aligned in the same direction, and further increase in the external magnetic field will not result in any additional magnetization.

2. How does magnetic saturation affect ferrite magnets?

Ferrite magnets, also known as ceramic magnets, are made from a type of ceramic material that is highly resistant to demagnetization. However, they do have a limit to how much magnetic field they can withstand before reaching saturation. Once a ferrite magnet reaches its magnetic saturation point, any further increase in the external magnetic field will not result in any additional magnetization.

3. What factors can affect magnetic saturation in ferrite magnets?

The main factors that can affect magnetic saturation in ferrite magnets include the strength of the external magnetic field, the size and shape of the magnet, and the composition and quality of the ferrite material itself. Temperature can also play a role in affecting the magnetic properties of ferrite magnets.

4. How can I determine the magnetic saturation point of a ferrite magnet?

The magnetic saturation point of a ferrite magnet can be determined by testing the magnet's magnetic properties using specialized equipment, such as a magnetometer. This will measure the magnet's magnetic flux density, which will decrease as the magnet reaches its saturation point.

5. What are the applications of ferrite magnets and their magnetic saturation properties?

Ferrite magnets are commonly used in a variety of applications, including speakers, motors, and generators. Their high resistance to demagnetization makes them ideal for these types of devices, as they can maintain their magnetic properties over a long period of time. Understanding the magnetic saturation point of ferrite magnets is important in designing and using these magnets effectively in different applications.

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