What is the difference between the performance grades N35 and n52 of NdFeB magnets?

What are N35 and n52 magnets? From their grades, they are sintered NdFeB magnets. Both magnets have the same intrinsic coercivity Hcj level, higher than 12 kOe (in CGS) or 955 Ka / M (in SI). It is also obvious that their maximum magnetic energy product (BH) max is about 35 and 52mgoe respectively. This huge difference means that the magnetic properties of n52 magnet are about 49% more than those of N35 magnet. In other words, a motor or device using an n52 magnet will have higher performance than a motor or device using an N35 magnet, and it will be smaller and lighter.

Demagnetization curve of N35 magnet and n52 magnet

N35 and n52 magnets are sintered NdFeB magnets. Why are their (BH) max so different? Is it a quality problem?

The answer is definitely not. It should be noted that the classification of permanent magnets is only based on their magnetic properties and has nothing to do with their quality. A specific grade is a macroscopic property produced by the composition and microstructure of the material. In order to achieve the required level or relative magnetism, it can be operated and controlled through material composition and production process.

Although they have the highest value of N50% in some commercial applications, they have the highest cost in some applications at room temperature (about 35%). Among sintered NdFeB magnets, N35 magnet is the most widely used. Compared with other permanent magnets (such as ceramic / ferrite magnets), the typical (BH) maximum is about 4mgoe, and the power of N35 magnet is almost 8-9 times that of the latter. In some cases, it does require NdFeB magnets with higher (BH) values, N45, N48 and N50 magnets are strong enough. Through structural design and optimization, using these levels of magnets instead of n52 magnets can achieve the target performance at a lower cost.