What Is the Difference of NdFeB in Different Grades

Understanding NdFeB Grades

NdFeB magnets are designated by a grade number such as N35, N42, N52, etc. This number primarily indicates the maximum energy product (BH)max, measured in Mega-Gauss Oersteds (MGOe). It tells you how strong the magnet is.

Key Performance Parameter Differences

Different NdFeB grades vary significantly in these critical performance parameters:

Maximum Energy Product (BH)max:

Core grading criterion

Example: N35 about 35 MGOe, N52 about 52 MGOe

Remanence (Br):

Higher grades have greater remanence

N35: ~1.17-1.22 Tesla

N52: ~1.45-1.48 Tesla

Coercivity (Hcb, Hcj):

Demagnetization resistance improves with grade

High Hcj grades suit high-temperature applications

Operating Temperature:

Standard grades (N series): up to 80°C

High-temp grades (M, H, SH, UH, EH): up to 200°C

 

Suffix	Max Operating Temp
No suffix	~80°C
H	~120°C
SH	~150°C
UH	~180°C
EH	~200–240°C

Grade Categories and Typical Applications

Grade	Energy Product (MGOe)	Characteristics	Typical Applications
N35-N40	35-40	Cost-effective, basic performance	Speakers, small motors
N42-N45	42-45	Balanced performance/price	Power tools, consumer electronics
N48-N52	48-52	High performance	Precision instruments, medical devices
35M-52M	35-52	Medium temp stability (100°C)	Automotive components
30H-48H	30-48	High temp stability (120°C)	Industrial motors
28SH-42SH	28-42	Super high temp (150°C)	Aerospace applications
30UH-38UH	30-38	Ultra high coercivity	Wind turbine generators
28EH-35EH	28-35	Extreme environment stability	Oil exploration equipment

 

How to Choose the Right NdFeB Grade?

 

Criteria	Recommended Grade
Low cost, general use	N35–N42
High magnetic strength	N50–N52
High temperature resistance	N35SH, N42UH, N48EH
Corrosive environments	Use coated magnets or epoxy-covered grades
Miniaturized designs	Opt for higher grades to reduce size

Special Grade Variants

Heavy Rare Earth-Free grades: Achieve high coercivity through grain boundary diffusion

Anisotropic bonded NdFeB: Complex shapes possible but lower energy product

High resistivity versions: Reduce eddy current losses for high-frequency use

 

Future Development Trends

New formulations achieving higher coercivity without sacrificing energy product

Heavy rare earth reduction technologies

New materials for extreme environments above 400°C