Study On Microstructure And Magnetic Properties Of SmCo/FeCo Nanocomposite Magnets Prepared By Rolling Strong Deformation

Nanocomposite magnets are composed of nanoscale hard-and soft magnetic phases.It is a new type of magnets which the theoretical magnetic energy product is much larger than that of single-phase magnets.Some results show that the high performance nanocomposites require a high fraction of soft phase with a small grain size?<10 nm?,a uniform phase distribution and an obvious orientation of the hard magnetic phase.Many preparation techniques have been used in bulk nanocomposites,but hard magnetic phases are difficult to form easy magnetization axis orientation in soft phase content greater than20%.Therefore,a preparation technology of a nanocomposite magnet with strong texture and high performance is our diligent pursuit.In this dissertation,a new method of preparing SmCo nanocomposite magnets,rolled deformation technology,is provided.The main contents are as follows:First,the development of permanent magnets is briefly introduced,and the preparation technology,property and structure testing technology of nanocomposite permanent magnets and SmCo-base permanent magnets are introduced in detail.Then,we use high energy ball milling technology to prepare three kinds of amorphous precursors.These precursors are carried out hot rolling at different temperatures,and then study the microstructure and magnetic properties of the hot rolled magnets.Finally,we prepare SmCo/FeCo nanocomposite magnets by hot rolling and high pressure heat treatment separately,and study the magnetic properties and microstructure of the magnets prepared by two methods.It is found that a magnet with fine grain size?10nm?,obvious texture of the SmCo₇ phase and large size have been successfully prepared by hot rolling deformation method.The energy product of the hot rolled magnets is 21MGOe.And we analyse the reasons for the high performance of the hot rolled magnets in detail.