What is better for neodymium iron boron plating?

Neodymium iron boron magnet is easy to corrode, so in the process of neodymium iron boron magnet becoming a finished product, electroplating treatment is needed to achieve anti-corrosion, so as to prolong its service life. What are the common neodymium iron boron surface coatings? What is better for neodymium iron boron surface electroplating?
What is better about neodymium iron boron surface plating? First of all, what should we have on neodymium iron boron surface?

Introduction of common Electrodeposited coatings on NdFeB magnets

NdFeB high intensity magnetic electroplating can adopt different electroplating processes according to the different use environment of products, and the surface coating is also different, such as zinc plating, nickel plating, copper plating, tin plating, precious metal plating, epoxy resin, etc. generally, the three processes of zinc plating, nickel plating + copper + nickel, nickel plating + copper + electroless nickel plating are the mainstream.
The advantages and disadvantages of NdFeB coatings are as follows:

1. Galvanizing:

• Advantages: certain strength and corrosion resistance (mostly used for magnet in servo motor and linear motor).
• Disadvantages: damage remanence to a certain extent.

2. Epoxy resin:

• Advantages: good adhesion, corrosion resistance, (mostly used for wind power generation, magnets used in automotive motors).
• Disadvantages: not scratch resistant, some degree of damage remanence.

3. Nickel copper nickel:

• Advantages: high strength, scratch resistance and corrosion resistance (used for some magnets in elevator motors).
• Disadvantages: damage remanence (do not use this coating without special requirements).

4. Aluminum plating:

• Advantages: it has certain corrosion resistance, and basically does not affect the remanence (mostly used in compressors and other magnets used in oil immersed environment).
• Disadvantages: lack of sacrificial protection, easy to scratch.

5. Phosphating and passivation

• Advantages: no influence on remanence (used in oil immersion environment, glue filling environment or other environment that can isolate air).
• Disadvantages: only temporary rust protection can be provided during transportation.

Conclusion:

From the price point of view: nickel plating is the most expensive, followed by zinc plating, and finally phosphating.
From the aesthetic point of view: nickel plating is the best, followed by zinc plating, and finally phosphating.
In terms of corrosion resistance, nickel plating is the best, followed by zinc plating and phosphating.
From the perspective of appearance color: nickel bright silver, zinc dark silver, phosphating dark gray.
PS: only zinc and nickel are suitable for direct plating on the surface of NdFeB magnet, so the multi-layer plating technology is generally implemented after nickel plating. At present, it has broken through the technical difficulty of direct copper plating on NdFeB, and direct copper plating followed by nickel plating is a development trend. Such coating design is more conducive to the thermal demagnetization index of NdFeB components to meet the needs of customers.