Preparation And Magnetic Properties Of Nanocomposite Permanent Magnetic Materials

Nano-composite permanent magnet materials are the latest generation of permanent magnet materials.The preparation of the nano-composite permanent magnet material comprises the metal smelting,the melt-spinning to prepare the thin strip,the low temperature nitriding.Nd Fe₁₂N has a lower rare earth amount than Nd₂Fe₁₄B.The Nd Fe₁₂N/α-Fe nanocomposite permanent magnet material can further reduce the amount of rare earth elements,thereby reducing the preparation cost of the material.The effects of melt-spinning roll speed on the microstructure and magnetic properties of the material were studied by preparing Nd₂Fe₁₄B/α-Fe nanocomposite permanent magnet materials.The effects of the addition of Ti and Nb on the microstructure of Nd₂Fe₁₄B/α-Fe nanocomposite permanent magnet materials were also studied.The Nd Fe₁₂N/α-Fe nanocomposite permanent magnet material with more severe process conditions was prepared by the experience of preparing Nd₂Fe₁₄B/α-Fe nanocomposite permanent magnet materials.The main conclusions are as following:The Fe grain size is obviously affected by the cooling rate.When the cooling rate is faster,the Fe grain size is smaller,and when the cooling rate is slower,the Fe grains grow significantly.A higher cooling rate suppresses the grain growth of the Fe phase,thereby controlling the grain size of theα-Fe phase.In the process of preparing Nd（Fe Ti Nb）₁₂N/α-Fe nanocomposite permanent magnet material ingot by vacuum arc melting furnace,it is found that the phase transformation of Nd-Fe alloy ingot is related to cooling rate,when the cooling rate is large,the 1:12 phase and the 1:9 phase of the metastable phase are easily formed,and when the cooling rate is low,the 2:17 phase and the 5:17 phase are easily formed.The addition of Nb element can effectively reduce the grain size of Fe phase in Nd（Fe Ti Nb）₁₂N/α-Fe nanocomposite permanent magnet material ingot.This is because the energy of the Fe-Nb system is low,which limit the growth ofα-Fe grain during the solidification process,and then make the grain size decrease from 500 nm to 200 nm.Figure 51;Table 6;Reference 54...