Study On Magnetic Properties Of Fe₃B/Nd₂Fe₁₄B Type Nanocrystalline Composite Permanent Magnets And Primary Discussion Of Bonded Magnets

Nanocrystalline composite permanent magnetic material is a new type of permanent magnetic material developed in recent years, that is consisted of soft and hard magnetic phases in the nanoscale, shows single ferromagnetic phase's magnetization and antimagnetization characteristics by exchange couple effect between soft and hard magnetic phases, and possesses remanence enhancement effect. Its maximum energy product (BH) _max can get 1 MJ/m³ theoretically, which exceeds any single-phase permanent magnetic materials; And it maybe developed to be a further novel generation of bonded permanent magnetic material, owing to the low rare earth content, high chemical stability, low costs, high practical value and good applications in the future.But the exchange couple interaction between soft and hard magnetic phases is belong to short-range exchange interaction, if in order to obtain high magnetic properties, then do control two phases' grain size and improve microstructure by ingredient optimizing, process improving to more improve magnetic properties.In the paper, though low Nd-content's (containing 4.5at%) nanocomposite permanent magnetic material properties are lower than high Nd-content's, however, due to high remanence, very low costs and application in many low request fields, the present research work is meaningful.First, discussing 4.5at% Nd-content's nanocomposite permanent material Nd_4.5Fe_74.5+xB_21-x (with x varying between 0 and 4 in increments of 1), while the basic component B is to some extent, permanent magnets' properties is optimum. Last result shows that 20at% B-content's permanent magnet's properties are optimum.Second, to investigate the change of Tb-content causing accordingly magnetic properties' change, the sample Nd_4.5-xTb_xFe_75.5B₂₀ (with x varying between 0.25 and 1.25 in increments of 0.25)...