Guide to Neodymium Magnet Grades Performance and Uses

When designing high-performance motors or selecting magnets for precision instruments, professionals often encounter perplexing grade labels like N35, N42, and N52. These alphanumeric codes represent crucial performance metrics that determine a magnet's suitability for various applications.

Neodymium Iron Boron (NdFeB) magnets, renowned for their exceptional magnetic properties, dominate modern industrial and consumer electronics applications. The grade designation follows a standardized format where "N" signifies NdFeB composition, and the subsequent numbers indicate the Maximum Energy Product (BHmax) measured in Mega-Gauss Oersteds (MGOe).

Key grade comparisons:

• N35: 35 MGOe (entry-level performance)
• N42: 42 MGOe (balanced performance)
• N52: 52 MGOe (premium performance)

Supplementary letters denote thermal stability—a critical factor for high-temperature applications where demagnetization becomes a concern:

• M: Stable to 100°C
• H: Stable to 120°C
• SH: Stable to 150°C
• UH: Stable to 180°C
• EH: Stable to 200°C
• AH: Stable to 230°C

Beyond grade numbers, four key metrics define magnet performance:

• Remanence (Br): Residual magnetic flux density after external field removal
• Coercivity (Hc): Resistance to demagnetization
• Intrinsic Coercivity (Hci): High-temperature stability
• Maximum Energy Product (BH)max: Total magnetic energy storage capacity

Market-available grades span N35 through N58, with distinct use cases:

• Consumer Electronics (N42-N48): Smartphone speakers, sensors
• Industrial Systems (N50-N52): High-performance motors, medical devices
• Specialized Applications (N55+): MRI systems, particle accelerators

Optimal magnet selection requires evaluating:

• Required magnetic force
• Operating temperature range
• Geometric constraints
• Cost-performance tradeoffs
• Supplier quality assurance

Industry advancements focus on:

• Higher-grade materials (N60+)
• Enhanced thermal stability
• Cost-reduction through manufacturing optimization
• Eco-friendly production methods