Improved Electrical Insulation of Rare Earth Permanent Magnetic Materials With High Magnetic Properties

Rare earth permanent magnetic materials are typical electrical conductor, and their magnetic properties will decrease because of the eddy current effect, so it is difficult to keep them stable for a long enough time under a high frequency AC field. In the present study, as far as rare earth permanent magnets are concerned, for the first time, rare earth permanent magnets with strong electrical insulation and high magnetic performance have been obtained through experiments, and their properties are as follows: (1) Sm2 TM17: Br = 0.62 T, j He = 803.7 kA/m, (BH)m = 58.97 kj/m3, ρ = 7 Ω · m; (2) NdFeB.- Br = 0.485 T, jHc = 766.33 kA/m, (BH)m=37.96 kj/m3, ρ = 9 Ω · m. The magnetic properties of Sm2TMi7 and NdFeB are obviously higher than those of ferrite permanent magnet, and the electric insulating characteristics of Sm2TMi7 and NdFeB applied have in fact been approximately the same as those of ferrite. Therefore, Sm2TM17 and NdFeB will possess the ability to take the place of ferrite under a certain high frequency AC electric field.