Demagnetization is the loss of magnetic field strength in magnets. Every magnet has a specific temperature, which is called the Curie temperature, at which it loses its magnetism. If magnets cool to room temperature, they may not regain previous super strong magnetic strength.

 

 

What causes strong neodymium magnets to demagnetize?

 

1. Influence of external magnetic field

     External magnetic fields, especially strong magnetic fields, can cause magnets to lose strength. The alignment of the magnetic domains can be disrupted when exposed to the north and south poles of another magnet.

 

2. Effects of heat exposure

     Heating permanent rare earth neodymium magnets to the Curie temperature causes its magnetic domains to randomize. Even if the magnet cools down, its original magnetic force may be reduced.

 

3. The role of working temperature

     Magnets' operating temperature is the highest temperature the magnets can withstand without significant loss of magnetic force. Neodymium magnets have a maximum operating temperature above which they may become demagnetized.

 

 

How to determine if neodymium magnets have been demagnetized?

 

     One must observe its magnetism and properties to determine whether strong power neodymium magnets have been demagnetized. Loss of strength or weakening of the magnetic field may be indicative signs. However, to understand the complete guide to demagnetization, one should understand the inherent properties of magnets such as permeability and temperature tolerance. Using tools or exposing a magnet to another magnet (such as an old magnet from the North) can provide further insight into its current state.

 

 

How to remagnetize a demagnetized neodymium magnet?

 

1.Make sure the demagnetized magnets are at room temperature.

 

2.Use stronger magnets or current to expose the demagnetized magnet to a strong magnetic field.

 

3.Make sure the magnets are aligned with the magnetization direction.

 

     PS：Make sure the magnets are only heated to its Curie point. Additionally, instruments are used to measure the strength that the magnet regains after remagnetization.

     Ndfeb magnets can be divided into bonded NdFeb and sintered NdFeb. The difference between the two magnets is mainly in the production process: bonded neodymium magnet is injection molding by adding NdFeb magnetic powder to the adhesive; sintered neodymium magnet is vacuumed and molded by high temperature heating.

 

     1. Custom sintered neodymium magnet

 

 

     In the process of sintering magnet manufacturing, neodymium magnet powder is mixed with appropriate additives and heated by high temperature sintering process. In the sintering process, the neodymium magnet powder particles will be combined to form a stable magnetic structure, thus forming a magnet with strong magnetism. Generally, through sintering, only blank can be produced, and then through mechanical processing (such as wire cutting, slicing, grinding, etc.) to become a magnet of various shapes. Sintered NdFeb is a hard and brittle material that is difficult to process, with large loss during processing. But the advantage is that sintered magnets usually have a high magnetic force and magnetic energy product, and have good temperature stability.

 

     Sintered Ndfeb is generally divided into axial magnetization and radial magnetization, and the magnetization direction can be customized according to the required work needs, while sintered Ndfeb has poor corrosion resistance and is easy to oxidize, so it is necessary to deposit on its surface, common nickel plating, galvanized, epoxy plating and so on.

     

     2. Custom bonded neodymium magnet

 

 

     The bonded neodymium magnet is used adhesive to bond the neodymium magnet powder with other metal elements, so it is magnetic in all directions and resistant to corrosion. In the manufacturing process, neodymium magnet powder and adhesive are mixed to form a magnet by pressure or injection molding. Because it is molded by injection molding, the density is generally only 80% of the theoretical, and the magnetism is weaker than the sintered neodymium magnet. But the manufacturing method of bonded neodymium magnets allows for more complex shapes and structures, and can be used in combination with other materials.

 

     The above is the introduction of the difference between the production processing technology of bonded NdFeb and sintered NdFeb. Both types of custom neodynium permanent magnets have their advantages and application scenarios. Sintered magnet is commonly used in applications that require high magnetic force and temperature stability, such as engines, sensors, and nuclear magnetic resonance equipment. Bonded magnet is suitable for applications that require custom shapes and structures, such as magnetic pusher pins, magnetic labels, etc.

 

 

     In short, the manufacturing process of sintered magnet and bonding magnet is different, and the choice of the appropriate process depends on the specific application needs.