NdFeB magnets are very easily corroded. Therefore, most of the finished products need to be electroplated or painted. Conventional surface treatments include nickel plating (nickel copper nickel), zinc plating, aluminum plating, electrophoresis and so on. If working in a confined environment, phosphating can also be used.
Neodymium iron boron magnets are currently widely used and rapidly developing magnet products. NdFeB has been widely used from its invention to the present, and it has only been more than 20 years. Because of its high magnetic properties and easy processing, the price is not very high, so the application field is expanding rapidly. At present, the magnetic energy product of commercial NdFeB can reach 50MGOe, which is 10 times that of ferrite.
NdFeB magnet is also a powder metallurgy product, and its processing method is similar to that of samarium cobalt. At present, the maximum working temperature of NdFeB is about 180 degrees Celsius. For harsh environment applications, it is generally recommended not to exceed 140 degrees Celsius.
The maximum energy product of NdFeB strong magnet is 5~15 times that of sintered ferrite, and the intrinsic coercivity is 5~10 times that of ferrite and 6~10 times that of AlNiCo; the potential of NdFeB The magnetic properties are very high. Theoretically, its magnetic energy product can reach 527kJ/m3 (66MGOe), and it can even absorb objects 640 times heavier than themselves. Because sintered NdFeB is easy to corrode, its application has limitations; when used in high humidity, high temperature, high acid and high alkali environments, sintered NdFeB must be surface coated, and the coating methods that can be adopted are electroplating (Zn, Ni, NiCuNi, Au, etc.), electrophoresis (epoxy resin), parylene, and combinations of these coatings;
Recently, with the technical innovation of the composition and process, the corrosion resistance and temperature stability have been significantly improved. However, the temperature stability of NdFeB materials is still not good so far, and the magnetic flux loss at high temperatures is still relatively large.