If you've ever purchased a NdFeB magnet, you surely know that almost all NdFeB magnets have a coating, so why don't ferrite magnets need a coating?
First of all, let us know about ferrite magnets, which are non- metallic magnetic materials, also known as magnetic ceramics, so there is basically no corrosion problem. It can be seen everywhere in life. For example, the speaker magnet in the radio is a ferrite magnet.
The magnetic performance of ferrite is not high. It is hard and brittle, but at the same time, it has many advantages,it is not easy to demagnetize, not easy to corrode, and it is cheap.
Similar to ceramics, it is generally formed by molds and sintered, and it is difficult to be machined, so most ferrite products have simple shapes and large dimensional tolerances.