Key takeaways
- Sintered NdFeB is a dense magnetic body; polymer-bonded magnets contain magnetic powder in a binder.
- Bonded magnets include isotropic and anisotropic materials made by compression or injection molding. Their energy products differ.
- Aichi MAGFINE’s 2018 sheet lists finished anisotropic compression-bonded MF14C at 22 MGOe, MF16C at 20 and MF18C at 19.5. Bonded NdFeB is not universally excluded above 15 MGOe.
- Use the finished-magnet specification. Powder values and hot-deformed dense-magnet values are not interchangeable with polymer-bonded properties.
Overview
Overview
Sintered and polymer-bonded NdFeB need different feedstock and processing. Compression-bonded and injection-bonded parts also differ in powder loading, binder and achievable shape. Anisotropic bonded materials require alignment during molding. Compare named finished materials rather than assigning one ceiling to the whole bonded family.
Side-by-side
Side-by-Side Comparison
Reference properties and design questions. A count of comparison points does not establish a material or supplier recommendation.
| Criterion | Sintered NdFeB | Bonded NdFeB |
|---|---|---|
| Structure | Dense sintered magnetic body | Magnetic powder in a polymer binder |
| Energy-product example | N42 reference: 40–43 MGOe at 20°C | MAGFINE MF14C compression-bonded example: 22 MGOe |
| Production route | Press, sinter and finish; route depends on geometry | Compression or injection molding with a selected binder |
| Orientation | Specified during manufacture | Isotropic or aligned anisotropic material |
| Temperature limit | Material curves and magnetic loading | Material curves, magnetic loading and binder limits |
| Geometry | Confirm pressing and finishing route | Confirm molding, alignment and tool design |
| Protection and handling | Qualify for the environment | Qualify binder, exposed material and any coating |
| Cost | Quote the complete part | Quote the complete part and tooling |
Confirm source conditions and the actual part requirements before using reference values as acceptance limits.
Use cases
Conditions for considering each option
When Sintered NdFeB wins
- The selected sintered material meets output requirements within the package.
- The proposed pressing and finishing route meets the drawing.
When Bonded NdFeB wins
- A specified bonded material meets the magnetic and thermal requirements.
- Molding provides useful geometry or assembly features at the required volume.
How to choose
Decision Framework
Decision framework
Compare the finished materials at the design temperature. Include powder alignment, binder, geometry and tooling. A requirement above 15 MGOe does not automatically rule out bonded NdFeB. Confirm that a cited value describes the finished molded magnet, not loose powder or a dense hot-deformed product.
Specs
Related NdFeB Grades
N42
80°C classN42 reference: 40–43 MGOe at 20°C, with a nominal 80°C temperature class.
Reference; drawing review required
N42H
120°C classN42H reference: 40–43 MGOe at 20°C, with a nominal 120°C temperature class.
Reference; drawing review required
N42SH
150°C classN42SH reference: 40–43 MGOe at 20°C, with a nominal 150°C temperature class.
Reference; drawing review required
N45SH
150°C classN45SH reference: 43–46 MGOe at 20°C, with a nominal 150°C temperature class.
Reference; drawing review required
N48SH
150°C classN48SH reference: 45–48 MGOe at 20°C, with a nominal 150°C temperature class.
Reference; drawing review required
Industries
Related Applications
Robotics
NdFeB design inputs for robot joint motors, compact actuators and servo drives.
EV Motors
NdFeB magnet design inputs for permanent-magnet traction motors, auxiliary drives and e-axles.
Industrial Automation
NdFeB magnets for stepper motors, servo drives, linear actuators, magnetic couplings, and factory automation equipment across European and North American manufacturing.
Questions
Frequently Asked Questions
What is the difference between sintered and bonded NdFeB?
+
Sintered magnets are dense magnetic bodies. Polymer-bonded magnets contain selected magnetic powder in a binder. Isotropic and anisotropic bonded grades, and injection and compression molding, have different properties and design limits.
Can bonded NdFeB replace a sintered magnet?
+
Only after evaluation of the complete magnetic circuit, temperature, binder and geometry. Aichi publishes anisotropic compression-bonded examples above 15 MGOe, so that value is not a family-wide exclusion.
Which route is cheaper?
+
Compare the finished-part quotation, tooling, inspection and assembly costs. Geometry and volume matter; a universal per-volume discount is not established by the material names.
Need help deciding?
Share your drawing, operating conditions and acceptance requirements for review. Human response within 1 business day.