Do all grades of Nd-Fe-B material still need to be coated/plated? 2013-12-28
Nd-Fe-B magnets have improved dramatically over the last 10 years. But they still contain iron and other reactive phases, and will rust. Nd-Fe-B is a blended powder before it is pressed into a magnet. The better the powder is mixed, the less "free" iron is available [small clumps of iron that did not mix with the other chemicals].
HSMAG Permanentmagnet recommends that Nd-Fe-B magnets be coated. This greatly extends the lifetime of the magnet. The benefit over time is great. Newer, uncoated Nd-Fe-B materials can be used for prototypes and experiments as long as there is not an expectation that the material will remain rust free, particularly in harsh environments.
