Neodymium Magnet Properties and How Magnets are Rated
Neodymium Magnet Grades Explained
Magnetic grades of Neodymium magnets are graded based on their maximum
energy product, which is a measure of their magnetic strength. The
NdFeB grades range from N35 to N52, with N52 being the highest grade currently
available.
Grading System
- The number following the "N" represents the maximum energy product in Mega-Gauss Oersteds (MGOe).
- For example, an N45 grade magnet has a maximum energy
product of 45 MGOe, while an N52 magnet has a maximum energy product of
52 MGOe. - The higher the grade number, the stronger the magnetic field the magnet will generate.
Temperature Ratings
- Some grades may also have a letter following the number, such as "M", "H", "SH", "UH", or "EH".
- These letters indicate the magnet's maximum operating
temperature, with higher letters corresponding to higher temperature
ratings. - For example, an N45M magnet has a maximum operating temperature of 100°C, while an N42SH magnet can withstand up to 150°C.
Applications
- Higher-grade magnets are typically used when the
highest performance is needed, such as in specialized applications or
devices that require a very strong magnetic field.
Below table summarizes the different NdFeB Grades:
| Grade | Br (KG) | HcB (KOe) | Hci (KOe) | BHmax (MGOe) | Tmax |
|-------|---------|-----------|-----------|--------------|------|
| N35 | 11.8-12.2 | ≥10.9 | ≥12.0 | 33-36 | 80°C / 176°F |
| N38 | 12.2-12.6 | ≥11.3 | ≥12.0 | 36-39 | 80°C / 176°F |
| N40 | 12.6-12.9 | ≥11.4 | ≥12.0 | 38-41 | 80°C / 176°F |
| N42 | 12.9-13.3 | ≥11.5 | ≥12.0 | 40-43 | 80°C / 176°F |
| N45 | 13.3-13.7 | ≥11.0 | ≥12.0 | 43-46 | 80°C / 176°F |
| N48 | 13.7-14.1 | ≥10.5 | ≥11.0 | 45-49 | 80°C / 176°F |
| N50 | 14.0-14.5 | ≥10.5 | ≥11.0 | 47-51 | 80°C / 176°F |
| N52 | 14.3-14.8 | ≥10.5 | ≥11.0 | 49-53 | 80°C / 176°F |
| N55 | 14.7-15.1 | ≥10.5 | ≥11.0 | 53-56 | 80°C / 176°F |
The key properties and magnet terminology shown in this table are:
- Br (KG): Residual flux density, a measure of the material's ability to retain magnetism
- HcB (KOe): Coercivity, a measure of the material's resistance to demagnetization
- Hci (KOe): Intrinsic coercivity, a measure of the material's resistance to internal demagnetization
- BHmax (MGOe): Maximum energy product, a measure of the material's maximum magnetic strength
- Tmax: Maximum operating temperature before significant loss of magnetism
In summary, the grading system for neodymium magnets is
based on their maximum energy product, which determines their magnetic
strength. This answers the question "how to measure the strength of a magnet": The higher the grade number, the stronger the magnet, and the
additional letters indicate the maximum operating temperature the magnet
can withstand.
