The most common coating/plating is Nickel. It is actually a Ni-Cu-Ni layered process. Thickness is .0005” to .0007” typical. This can be thicker for challenging environments.
The next most common is epoxy coating. It’s a decent coating but not good for applications where the magnet might be exposed to physical abrasion. It is also more difficult to hold tight tolerances.
Other coatings available are: Zinc, Titanium Nitride, IVD Aluminum, Parylene, Tin, Silver, Gold. These processes are much more expensive and are not as amiable to high volume production.
- Typical tolerance for ground/coated/plated magnets is +/- .005”
- Ni coated magnets can be held to +/- .003” without cost implications
- We can hold tolerances to +/- .0005”