Coatings for Sintered NdFeB Magnets[/caption]

Sintered NdFeB magnet is produced by powder metallurgy technology. It is a kind of powder material with very strong chemical activity. There are tiny pores and cavities inside, which are easily corroded and oxidized in the air. The experimental results show that a 1cm³ sintered NdFeB permanent magnet will be completely oxidized and corroded if placed in the air at 150°C for 51 days. Therefore, strict anti-corrosion treatment must be carried out before use.

At present, NdFeB anti-corrosion treatment generally adopts electroplating, electroless plating, electrophoretic coating, phosphating treatment, and other methods. Among them, electroplating is widely used as a mature metal surface treatment method. 

The NdFeB electroplating process includes two important steps: pretreatment and electroplating.