Grades and properties of sintered NdFeB permanent magnets

When purchasing NdFeB magnets, which grade to buy is a question that all purchasers will be asked. N35, N38H, N40SH...

What do these complex grades represent? 

What are the differences between different gardes of magnets? 

How to choose the appropriate NdFeB magnet by grade?

According to the different intrinsic coercive forces HcJ, sintered NdFeB permanent magnets can be divided into seven series : N, M, H, SH, UH, EH and AH (TH).
In each series, the grades are subdivided according to the size of the magnet's residual magnetism Br and the maximum magnetic energy product BH (max).
The number represents the maximum magnetic energy product (BH)max of the product. The larger the number, the greater the maximum magnetic energy product.

The letters represent the classification of intrinsic coercivity. The further back the series, the greater the intrinsic coercivity.

There are four main indicators to measure the magnetic properties of sintered NdFeB products: Br remanence, Hcb coercive force, Hcj intrinsic coercive force and (BH)max maximum magnetic energy product

Under the same size, the higher the residual magnetism, the stronger the magnetic force of the magnet.

Coercive force and intrinsic coercive force are indicators of the magnet's ability to resist demagnetization. The higher the coercive force, the better the magnet's stability and temperature resistance.