2026-01-05 · SINOWIN INDUSTRIAL (VN)
HRE-Free Thermal Showdown: Can "Magnet Kings" Survive 120°C?
A practical selection guide estimating reversible/irreversible losses for N/M/H/SH HRE-free NdFeB at extreme temperatures.
As electrification accelerates, NdFeB permanent magnets remain core components in motors and sensors. HRE-free technologies are reshaping the landscape — delivering strong performance even under elevated temperatures.
Why Magnets Dislike Heat: Two Components of Thermal Loss
- Reversible loss: like a spring — magnetic flux decreases with temperature and fully recovers after cooling.
- Irreversible loss: the critical part. If the design exceeds the knee point, the magnet may not recover after cooling and requires re-magnetization.
Grade Performance at Upper Temperatures
| Grade | Upper Temp | Br coeff α (%/°C) | Hcj coeff β (%/°C) |
|---|---|---|---|
| N | 80°C | -0.12 | -0.60 |
| M | 100°C | -0.12 | -0.58 |
| H | 120°C | -0.11 | -0.58 |
| SH | 150°C | -0.10~-0.12 | -0.55 |
Total Flux Loss Estimates
- N (80°C): ~12.2% total loss
- M (100°C): ~14.6% total loss
- H (120°C): ~16.0% total loss
- SH (150°C): ~20.6% total loss