As compared with other permanent magnetic material, sintered NdFeB permanent magnetic material has some outstanding advantages such as high magnetic property and low cost, so that it has been widely developed and applied. At present, sintered NdFeB permanent magnetic material has been applied in many fields due to a relative higher comprehensive magnetic property.
However, new energy and environmental protection have obtained increased concern and become a developing trend, and a permanent magnetic material with a high coercivity and a high remanence is required. A permanent magnetic material with a high coercivity needs relative more expensive elements dysprosium and/or terbium. But if too much such elements are added, neither the requirement of high remanence can be meet, nor the light weight of motor and high availability of electric energy and wind energy can be obtained.
The coercivity of prepared permanent magnet material at present has a significant difference from a theoretical limit 80 kOe, and a relative high content of Dy and/or Tb is needed in order to improve the coercivity of the permanent magnet material at present. In addition, when the coercivity of the permanent magnet material is increased, the remanence may be decreased. Therefore, it is required to improve the coercivity with only a small decrease of the remanence of the permanent magnetic material by using a small amount of Dy and/or Tb.