Permanent Magnets: Quick Guide to Pros, Cons & Selection

Permanent magnets power modern tech but vary wildly in performance. Here’s a concise breakdown of key materials and how to choose them.

Key Metrics

• Energy (BHmax): Magnetic strength per volume.
• Coercivity (Hc): Resistance to demagnetization.
• Temperature Limit: Maximum operating heat.
• Cost: Material + processing expenses.

4 Major Types Compared

How to Choose in 3 Steps

1. Temperature:

   • Extreme heat (>300°C) → SmCo
   • Normal temps → NdFeB or Ferrite

2. Budget:

   • Lowest cost → Ferrite
   • Best performance → NdFeB

3. Environment:

   • Harsh (corrosion/radiation) → SmCo
   • Basic → Ferrite or NdFeB

Future Innovations

• Rare-earth-free magnets (e.g., Mn-Al-C).
• Recycling tech (95% NdFeB recovery).

• Heat-resistant NdFeB (250°C+ via new coatings).

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