Understand the Grade and Production Process of Sintered NdFeB Magnets

Grades of sintered NdFeB magnets

The differences in the grades of sintered NdFeB magnets are mainly reflected in their magnetic performance parameters, including remanence (Br), coercivity (Hcb), intrinsic coercivity (Hcj) and maximum magnetic energy product ((BH)max). Different grades of magnets have different performance characteristics to meet different application requirements.

The grades of sintered NdFeB magnets usually start with the N series, followed by numbers and letters representing temperature coefficients, such as N35, N38H, N40SH, N42UH, etc. The numbers represent the maximum magnetic energy product of the magnet. The larger the number, the higher the magnetic energy product and the stronger the magnetic force of the magnet.

The letters represent the classification of the intrinsic coercivity of the magnet, such as M for medium coercivity, H for high coercivity, UH for extra-high coercivity, EH for extremely high coercivity, and AH or TH for the highest coercivity.

The maximum energy product of permanent magnet materials is expressed as MGOe (MegaGaussOersteds). It represents the strongest point on the magnet demagnetization curve or BH curve. Simply put, the higher the grade of the magnet, the greater the magnetic field generated by the magnet, which means that the magnet has greater magnetism.

High temperature resistance of sintered NdFeB magnets

The high temperature resistance of sintered NdFeB magnets is related to their intrinsic coercivity. Different grades of magnets have different maximum operating temperatures, for example, the operating temperature of N38 is 80℃, while N38UH can reach 180℃.

In order to improve the high temperature resistance of sintered NdFeB magnets, alloy elements such as dysprosium (Dy), gadolinium (Gd), holmium (Ho) can be added to replace part of the neodymium element, which can improve the temperature resistance of the magnet.

Production process of sintered NdFeB magnets

Sintered NdFeB magnets adopt powder metallurgy process, including smelting, powderization, pressing, sintering and aging heat treatment steps.

Parameters such as smelting process, oxygen content, powder particle size, sintering temperature and tempering process in the production process will affect the performance and temperature resistance of the magnet.

Application fields of sintered NdFeB magnets

Sintered NdFeB magnets are widely used in electronics, electricity, machinery, medical, toys, packaging, hardware, aerospace and other fields.

In general, understanding the differences in grades and high temperature resistance of sintered NdFeB magnets is essential for selecting suitable sintered NdFeB magnets to ensure that they can perform at their best in specific applications.