In This Guide
Decoding the Grade Name
Every NdFeB grade follows a simple naming convention: a letter prefix (N for standard), a number (BH Max in MGOe), and an optional temperature suffix.
- •N = Standard (Sintered NdFeB)
- •Number = Nominal BH Max (e.g., N52 = 52 MGOe)
- •No suffix = 80°C max operating temperature
- •M = 100°C, H = 120°C, SH = 150°C, UH = 180°C, EH = 200°C, AH = 220°C
Higher Grade ≠ Always Better
N58 is the strongest grade in the production range, but the top energy tiers come with lower coercivity, higher cost, and more brittleness. Most applications are perfectly served by N42 or N45 grades. Over-specifying wastes money without meaningful performance improvement.
- •N35–N40: Cost-effective, good for general-purpose applications
- •N42–N48: Sweet spot — best performance-to-cost ratio for motors and sensors
- •N50–N58: Ultra-high performance, use only when every gram matters
Pro Tip: A well-designed magnetic circuit with N42 will often outperform a poorly designed circuit with N52. Invest in circuit optimization before chasing higher grades.
Temperature Grade Selection
The temperature suffix is arguably more important than the number. Under-specifying the temperature grade causes irreversible demagnetization in the field — the most common cause of magnet failures we see.
- •Always add a safety margin: if your max temp is 100°C, specify SH (150°C) grade
- •Consider the Permeance Coefficient: thin magnets with large air gaps are more susceptible to demagnetization at temperature
- •GBD-processed magnets offer high-temp grades (SH, UH, EH) at near-standard cost — ask us about this option
How to Read a Magnet Datasheet
Key parameters to check on any NdFeB datasheet: Br (remanence), Hcj (intrinsic coercivity), BH Max (energy product), and the demagnetization curves at various temperatures. The curves tell the full story — the numbers are just summary statistics.
Request a sample kit with N35, N42, and N52 grades to compare performance in your application.
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