Ndfeb magnets are very vulnerable to corrosion. Therefore, most of the finished products need to be electroplated or coated. Conventional surface treatments include: nickel plating (ni-cu-ni), zinc plating, aluminum plating, electrophoresis, etc. If you work in a closed environment, you can also use phosphating.
Neodymium iron boron magnet is widely used and rapidly developed. Ndfeb from the invention to the present widespread application, also only more than 20 years. Because of its high magnetic properties and ease of processing, the price is not very high, so the application field is expanding rapidly. At present, the magnetic energy of commercial ndfeb can reach 50MGOe, 10 times that of ferrite.
Neodymium iron boron magnetic also belongs to powder metallurgy products, processing methods and samarium cobalt similar. At present, the highest operating temperature of ndfeb is about 180 degrees Celsius. For harsh applications, it is generally recommended not to exceed 140 degrees Celsius.
The maximum magnetic energy of ndfeb is 5~15 times of sintered ferrite, and the intrinsic coercivity is 5~10 times of ferrite, 6~10 times of al-ni-co. The potential magnetic properties of ndfeb are very high, theoretically reaching 527kJ/m3 (66MGOe) and even sucking up objects 640 times their own weight. Because sintered ndfeb is easy to corrode, its application has limitations; For applications in high humidity, high temperature, high acid and alkali environments, sintered ndfeb must be coated by electroplating (Zn, Ni, NiCuNi, Au, etc.), electrophoresis (epoxy resin), parylene, and a combination of these coatings.
Recently, with the technical innovation of composition and process, corrosion resistance and temperature stability have been improved significantly. However, up to now the temperature stability of ndfeb material is still not good, in high temperature magnetic flux loss is still large.