Effect of Temperature on Neodymium Magnets

In order to understand various characteristics of neodymium magnet, it is necessary to know how much maximum temperature is allowable for these magnets. It will also be interesting to understand if we go beyond that temperature then what is the possible outcome. One should therefore be able to read Demagnetization curve of these magnets. Let us try to understand various basic things about these magnets.

How much temperature is sustainable?

There are number of factors based on which the neodymium magnet may sustain. Following are few of them

  • Type of magnetic material
  • Temperature type of the magnet
  • Shape of magnet
  • How the magnet is positioned in a group

Type N neodymium magnets lose permanently at 80 degree C, while tapes and sheets lose at 85 degrees C and ferrite magnet loses at 250 degree C.

If you cool down vigorously then nothing happens to neodymium magnets, but in case of ferrite magnets they lose part of their magnetic property after you cool it below -40 degree C and magnetic sheets and tapes loses completely below -20 degree C.

Magnet’s property may lose at higher temperature. However, its property can be reversed to original strength by cooling it down and this process can be repeated as many times as you wish. This is called reversible loss.

If you heat the magnet beyond the working temperature and again try to cool down then its magnetic property will weaken permanently. This is called irreversible loss. This irreversible magnetic loss can only be regained by keeping them under strong external magnetic field. However, if you heat the magnet higher than above then its magnetic structure may change and it will lose its property permanently. In such case re-magnetization is not possible.

Duration of heating

In case of irreversible loss duration of heating does not have much influence as far as strength of loss is concerned where it is assumed that the temperature was uniform in all parts of the magnet. If you heat any thick magnet for very short duration then its outside temperature is much higher than its temperature inside the magnet. In such cases, the position of the magnet will decide the loss.

Magnet position and shape at temperature losses

Due to heating the magnet suffers irreversible loss. The loss depends not just on its temperature or type of magnet, but also on its position and shape within the group of magnets or any ferromagnetic material. By putting the magnet in some odd position or making it oddly shaped, you may achieve irreversible loss at much lower temperature too.

The temperature loss of a magnet follows certain rules. If the shape of the magnet is flat then it can suffer temperature loss at very low temperature. However, in case the ratio between its diameter and height is lesser than 4, then you can heat the magnet at much higher temperature without losing its property.

You can choose various types of neodymium magnet for different applications by visiting the website usneodymiummagnets.com/neodymium-disc-magnets.html.

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