What is the phosphating process of NdFeB magnets?

Neodymium iron boron (NdFeB) magnets have been widely used, and magnet products are developing rapidly. NdFeB magnets are the third generation of rare earth permanent magnets, which have been developed and applied for about 20 years. Because of its high magnetic function and easy processing, the price is not very high, so the application field is expanding rapidly.

So what is the phosphating process of NdFeB magnets?
At present, the magnetic energy product of commercial NdFeB magnets can reach 50 mgoe, which is 10 times that of ferrites. NdFeB magnets are easy to corrode. Therefore, most of the finished products need to be electroplated or coated.
The conventional choice of surface treatment for NdFeB magnetic materials includes nickel plating (Ni Cu Ni), zinc plating, aluminum plating, electrophoresis, etc. If in a closed working environment, we can choose phosphating method. When the magnet needs epoxy adhesive and coating, the adhesion of epoxy organic compounds (such as glue and coating) needs good wettability of the matrix.
There are two main purposes of phosphating treatment:

• 1. Process corrosion protection.
• 2. The surface wettability of NdFeB magnet was improved.

The phosphating process of NdFeB magnet surface is as follows: degreasing → washing → pickling → washing → surface adjustment → phosphating → sealing and drying.
Because of its good adhesion to the surface of porous magnet, salt spray resistance, acid resistance, alkali resistance, corrosion resistance and corrosion resistance. However, compared with spraying, it has poor hygrothermal resistance.