Review the protective layer and magnet together.
Consider corrosion protection for sintered NdFeB against its environment. Metallic plating, organic coatings and encapsulation have different conditions, and affect assembly and finished dimensions.
Local section of nickel–copper–nickel: Ni, Cu and Ni from the base outward. Layer thicknesses are exaggerated and not to scale.
Common finishes and review points.
| Reference finish | Characteristics | Confirm |
|---|---|---|
| Nickel–copper–nickel | Common metallic protection with a smooth finish. | Environment, adhesive compatibility, finished dimensions and protection requirements. |
| Zinc | A metallic protection option; surface condition varies with the process. | Passivation/appearance, fit, contact media and test conditions. |
| Epoxy coating | Organic protection; underlayers and construction depend on the process. | Coating integrity, bonding/curing, wear and chemical compatibility. |
These are reference options. A finish name alone does not guarantee waterproofing, insulation or salt-spray resistance. Confirm capability and criteria in the project specification.
Describe the environment before selecting protection.
| Condition | Review points |
|---|---|
| Dry indoor | Temperature, handling/assembly, appearance and finished dimensions. |
| Humidity or condensation | Humidity, condensation frequency, edge coverage, drainage and validation. |
| Water or other media | Composition, exposure method/duration and possible encapsulation. |
| Sweat or cleaning agents | Composition, concentration, exposure frequency and compatibility. |
| Temperature cycling | Review magnet, coating, binder and adhesive limits separately. |
| Adhesive assembly | Adhesive, surface preparation, curing temperature/time and loading. |
| Wear or impact | Contact frequency, loads, edges and cushioning, beyond a thin coating. |
Define the conditions before reviewing samples.
Provide media, temperature/humidity, exposure frequency, assembly/curing, finished dimensions, and test methods and acceptance criteria.
Salt-spray duration needs a test standard, sample condition and acceptance criteria; it is not service life. Coating temperature resistance is not the magnet operating limit.