Chinese Scientists Have Discovered A New Way To Enhance The Coercivity Of Rare Earth Magnetic Materials

- Jul 18, 2019-

On December 6, 2018, science and technology daily reported that the reporter learned from baotou rare earth high-tech zone that Dr. Song zhenlun, a researcher from ningbo institute of materials, Chinese academy of sciences, has successfully developed the "physical vapor deposition method and grain boundary diffusion method" technology, which can greatly improve the force of rare earth magnetic materials.

Coercivity is the decisive factor of the magnetization and retention time of permanent magnetic materials. "With the rapid increase in demand for new rare earth materials, the demand for magnetic properties of magnets is no longer limited to high residual magnetism and high magnetic energy," song told reporters.

According to introducing, the r&d team by physical vapor deposition, magnetron sputtering technology is orthogonal electric field and magnetic field on the anode (substrate), between the cathode (heavy rare earth material), make the argon gas between the electric field, magnetic field high-energy argon ion was inspired, by the impact of heavy rare earth target material to argon ion deposition to the substrate surface in the form of atoms, so as to realize in the excited state of high-energy heavy rare earth material evenly firmly attached to the base material surface, is advantageous to the subsequent high vacuum thermal diffusion process of heavy rare earth atoms.

And grain boundary diffusion technology, is a physical vapor deposition method after deposition of magnetic materials after high temperature vacuum diffusion, the heavy rare earth elements infiltrated ndfeb magnetic material such as internal, replace the Nd (Nd) elements to form high magnetocrystalline anisotropy field of heavy rare earth compounds, finally realizes the coercive force of magnetic materials increase greatly.

According to song zhenlun, the combination of physical gas-phase deposition method and grain boundary diffusion technology can improve the forcing force of sintered ndfeb permanent magnet products (by 2-3 brands on average), and reduce the addition of heavy rare earth by 60-70%. At present, the pilot production line of new technology has opened up all technical links, which can not only meet the technical requirements of low-weight rare earth grain boundary diffusion of permanent magnet materials, but also provide complete sets of equipment and process services to the outside world.