We sincerely welcome your business, and look forward to good cooperation. 
01CALL US
+86-574-87504597
03REQUEST INQUIRY
Product Inquire
When we heat a magnet, how does the magnet's magnetic field change?
Home » Blogs » knowledge » When we heat a magnet, how does the magnet's magnetic field change?
You are here: Home / Blogs / knowledge / When we heat a magnet, how does the magnet's magnetic field change?

When we heat a magnet, how does the magnet's magnetic field change?

Author: Site Editor     Publish Time: 2024-03-21      Origin: Site

The magnetic field of NdFeB magnets will become smaller when encountering high temperatures, because NdFeB magnets themselves have a transition temperature. Below this temperature, they show ferromagnetism, while above this temperature, they show no ferromagnetism (paramagnetism). This transition temperature is called the "Curie temperature". And when the temperature reach to 80℃, N35-N52 will lose all magnetism.  When the temperature reach to 220℃, N35AH will lose all magnetism. Some manufacturer choose heating method to demagnetize the magnet.

 

When we heat a magnet, how does the magnet's magnetic field change

 

Why the magnetic field of NdFeB magnets will become smaller when encountering high temperatures?


According to Ampere's molecular current hypothesis, the reason why NdFeB magnets can show magnetism is because the electrons in the molecules in the magnet move in the same direction. That is, the electrons rotate in same direction around the nucleus at high speed, so multiple magnetic fields in the same direction are superimposed. Macroscopically, it shows the magnetism of the magnet.

 

When a magnet is heated in a fire, its magnetism disappears. This is because the magnet is magnetic, and the movement of free electrons inside it has a certain directionality, so the magnet is magnetic. However, after heating, the direction of movement of the internal electrons becomes chaotic and loses directionality. , so the magnetism disappears and weakens.

 

If you heat a NdFeB magnet, the energy gained by the electrons will disrupt the movement of the electrons. Microscopically, there will be magnetic fields in many different directions. After the vector is added, the magnet will weaken macroscopically. Similarly, when a NdFeB magnet encounters a large external force (such as a hit or collision), the molecular current hypothesis will disrupt the movement of the original electrons, and the magnet's magnetism will weaken in an instant.

 

When we heat a magnet, how does the magnet's magnetic field change (2)

 

Why do magnets demagnetize when heated?


The magnetic molecules inside the unmagnetized magnet (the theory of molecular magnets) are randomly arranged. After the magnetization process, the magnetic molecules will be arranged regularly. At this time, the N pole and S pole of the magnetic molecules will face the same direction, making the magnet magnetic and becoming a magnet. If the magnet is heated, the arrangement of the magnetic molecules will be disrupted, and the magnet will lose its magnetism. If the magnet is heated to the Curie temperature, the arrangement of the magnetic molecules cannot be restored by itself, and the magnet will demagnetize.


Hello Customers

Mr. Thomas is a highly respected professional when it comes to magnet production and sales. He has over 20 years of extensive experience in the field of magnets, and his expertise and experience as a professional enable him to provide excellent services to his clients.

Mr. Thomas has become a trusted partner of his clients with his excellent communication skills and deep industry understanding. Not only can he answer customers' technical questions about magnet products, he can also provide targeted suggestions to ensure customers choose the products that best suit their needs.

Related Products

content is empty!

Related Blogs

content is empty!

Get in touch
Ningbo Bestway Magnet Co. Ltd. is a professional and high-tech company which is committed to research, manufacture and develop of Rare Earth Magnet since 2000 located in Ningbo, China.

Product Links

Get In Touch

     No.2 Meifang Road, Dongqian Lake
       Tourism Resort, Ningbo, Zhejiang,
       China.
 

     +86-574-87504597, 27788030

     +86-574-87506907, 87506697

       
thomas03@bwmagnet.com

Feedback
Get in touch
©  2019 Ningbo Bestway Magnet Co., Ltd.  All Rights Reserved.