The Nd-Fe-B strong magnet coating is usually plated with nickel, copper, chromium, gold, black zinc, blue and white zinc, epoxy resin, etc. Different electroplating, the surface of the magnet will have different colors, and the storage time is very long.
Nickel, zinc, epoxy resin: The effects of nickel, zinc, epoxy resin, and polypropylene glycol coatings on the magnetic properties of NdFeB magnets in three solutions were studied.
Polymer material＞Epoxy resin＞NI coating＞ZN coating
The results show that in acid, alkali, and salt environments, the polymer coating has the best protective effect on the magnet, the epoxy resin is poor, the NI coating is second, and the ZN coating is poor.
Zinc: The surface is silvery white. Can be used for 12 to 48 hours of salt spray. It can be bonded with some glue (such as AB glue), if electroplated, it can be stored for 2 to 5 years.
Nickel: The surface is stainless steel, the surface is not easy to oxidize, the appearance is good, and the gloss is good. The electroplating can pass the 12-hour/72-hour salt spray test. The disadvantage is that it cannot be bonded with glue, which will cause the coating to fall off.
Copper: Mostly in the hardware industry, the NdFeB industry is rarely used, and its appearance is yellow.
Chromium: The chromium plating industry is also relatively rare, and its electroplating cost is very high, which is not acceptable to general companies. However, it has a strong decomposition ability, and is difficult to react with other substances. Mainly used in places with strong acidity and alkalinity. Generally speaking, this is rarely chosen.
Black zinc: According to customer requirements, the surface treatment of the product is black. In the electroplating process, the main purpose is to add a black protective film on the basis of the chemical treatment of zinc plating. The film can also protect the product, increase the salt spray time, and prolong the oxidation time. However, its surface is easily scratched and loses its protective effect. Today, few people use it, and most of them are replaced by resin.
Epoxy resin: After nickel plating, add a layer of resin paint on the outside. This industry has only had a market in the past two years. It is developing very fast. Many people now use various electroplating products. Its biggest advantage is that you can achieve the color you want.