What are the grades of NdFeB magnets?

NdFeB magnets (Neodymium-iron-boron magnets) are primarily graded based on their maximum energy product ((BH)max) and intrinsic coercivity (Hjc), usually represented by a combination of letters and numbers. Common grades include the basic series from N35 to N52, and subsequent high-temperature series with specific letter suffixes, such as N35M, N38H, N42SH, N40UH, N38EH, and N30AH. The higher the number, the stronger the magnetic properties of the magnet; the later the letter suffix, the better the heat resistance.

Understanding the grading system of NdFeB magnets is the first step in selecting high-performance magnetic materials. The grade typically consists of three parts:

Prefix N: Represents Neodymium, the rare earth permanent magnet material.

Middle number: Represents its maximum energy product. For example, N52 is currently the strongest grade in commercially produced magnets.

Suffix letter: Represents the working temperature limit. If there is no letter, it is usually defaulted to 80°C.

Differences in applications of different grades of NdFeB magnets

NdFeB magnets are known as the "king of magnets" due to their excellent magnetic properties, but in actual industrial applications, a higher grade is not always better; it depends on the "match" to the application.

1. High energy product series (e.g., N52, N55)

These are used when maximizing volume efficiency is crucial. In space-constrained and temperature-stable electronic products (such as mobile phone linear motors, hard disk drives), high-grade NdFeB magnets can provide the greatest magnetic force or torque in the smallest volume.

2. High coercivity series (e.g., 38SH, 40UH)

These magnets are mainly used in permanent magnet motors. High temperatures are generated during motor operation, and if the coercivity of the NdFeB magnet is insufficient, irreversible demagnetization will occur. The SH and UH series can maintain high magnetic strength while resisting magnetic decay in high-temperature environments.

How to choose the right NdFeB magnet for your project?

As a professional user of powerful magnets, we recommend considering the following three dimensions when selecting a grade:

Working temperature: This is the key factor determining the grade suffix. If the working environment exceeds 100°C, you must choose an NdFeB magnet of grade M or higher.

Magnetic force requirements: If you only need simple fixing functions, the N35 grade offers the best cost-effectiveness; if precise sensing or powerful driving is required, you need to increase the numerical grade.

Surface treatment: Neodymium iron boron material is chemically active and easily oxidizes. Regardless of the grade chosen, it needs to be coated with nickel (NiCuNi), zinc (Zn), or epoxy resin.

With the development of new energy vehicles and intelligent manufacturing, the grading system for NdFeB magnets is constantly being improved. Precisely understanding the performance indicators behind each grade can not only optimize product structure but also effectively control production costs.