What are the possible reasons for demagnetizing of permanent magnets?

Neodymium Magnets are strong permanent magnets that made of PrNd metal, iron and boron. It is not common to observe the demagnetizing effect in such strong magnets, but it is still possible. Below are some of the reasons why permanent magnets can be demagnetized:

1. 1. High temperature lamination: in many cases, Neodymium Magnet needs to be laminated before it is assembled with other parts. Standard grades of neodymium magnets maintain a maximum working temperature of 80 Celsius, therefore when it goes through the lamination process (120 Celsius), demagnetizing effect occur.

1. 2. Hot pressing process: neodymium magnets go through hot pressing process before it is assembled with other parts. As the maximum working temperature of standard grades of neodymium magnets is 80 Celsius, demagnetizing effect occur in hot-pressing process due its high temperature (120-150 Celsius).

1. 3. Cheap raw material: Many suppliers tend to use cheap/lower grade material to keep cost low. Thus, cheap raw material is often mixed with other ingredients which affect the performance and stability of the magnetic force for the magnet both in short and long term.

1. 4. Transportation: For air transport, Neodymium magnets are considered dangerous goods that need to follow IATA Dangerous Goods Regulations as seen below.

• - Flux measurements of all packages containing magnets must measure less than 0.00525 gauss 15` from the package. If flux measurements are less than 0.002 gauss when measured 7` from the package, the package is not considered to contain Magnetic Material, and hence is not classified as Dangerous Goods. However, unless the package is extremely secure and there is no chance that the contents will shift or that shielding will be damaged in transit, it is safer to proceed as though the package falls under the DGR.

• - Packages containing magnetic materials must be clearly identified according to Packing Instructions 902. This calls for a "Magnetized Material" label to be affixed, and for a Shipper's Declaration of Dangerous Goods to be provided to the carrier.

• - Personnel responsible for shipping magnets by air are required by the Federal Aviation Authority (FAA) to be trained for that purpose and for those training records to be maintained. Contact your carrier for more information and guidelines.

Therefore, it is important to choose a magnet supplier with experience in exporting magnets as DGR need to be followed for magnets to be delivered to customers in safe/fast conditions.

1. 5. High magnetic field environment: When neodymium magnets are placed in a strong magnetic field environment, for example magnetizer or a demagnetizer , its N pole and S pole will change and its magnetic force will be affected as well.