Common Coating Routes
Actual performance depends on pretreatment, edge geometry, coating thickness and test method. Use samples and an agreed validation plan for critical environments.
Corrosion Protection Guide
Magnet Coating Selection Guide
NdFeB coating selection should follow the real environment, dimensional tolerance and assembly process—not appearance alone.
| Coating | Typical reason to select | Design note |
|---|---|---|
| Ni-Cu-Ni | General protection and metallic appearance | Common baseline; protect chipped edges |
| Zinc | Economical sacrificial protection | Color and passivation system vary |
| Epoxy | Improved barrier and dark appearance | Control edge coverage and handling damage |
| Parylene | Thin conformal barrier for complex shapes | Specify grade, thickness and adhesion test |
| Phosphate | Thin temporary protection / bonding preparation | Not a stand-alone solution for severe exposure |
Coating Is Part of the Tolerance Stack
State whether magnet dimensions apply before or after coating. Small magnets, tight air gaps and bonded assemblies may require thickness control on specific faces and masking of bonding or electrical contact areas.
What to Put on the RFQ
Describe the end-use environment and acceptance test instead of requesting a coating by name only.
- ✓Humidity, salt, chemicals and maximum temperature
- ✓Required coating and thickness range if mandated
- ✓Adhesive, overmolding or press-fit process
- ✓Salt-spray or pressure-cooker test method and duration
- ✓Cosmetic faces and allowable contact marks
Practical Answers
Frequently Asked Questions
Which coating is best for NdFeB magnets?
There is no universal best coating. Ni-Cu-Ni is a common baseline, while epoxy or parylene may suit specific barrier, thickness or assembly requirements.
Does coating prevent all corrosion?
No. Coating reduces exposure, but chips, porous edges, severe chemicals and poor assembly sealing can still cause corrosion. The complete environment must be reviewed.
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