Preparation of Bonded Magnets -Isotropic and Anisotropic Magnetic Particles(2)

Therefore, in the actual production, it is usually first to condense the magnetic powder to a partial amorphous state at a wheel speed higher than the optimal linear speed, and then adjust the crystallization state to an average grain size of 40nm through the crystallization treatment at 630℃, so as to achieve stable and good permanent magnet characteristics. The American Magquin Magnetic Company, which dominates the isotropic rapidly quenched Nd-Fe-B market, has adopted such a technological route for production.

Anisotropic rapidly quenched rare earth permanent magnetic powder prepared by HDDR process

HDDR process is a very effective means to produce anisotropic NdFeB magnetic powder. HDDR process including Hydrogenation - Disproportionation - dehydrogenation - restructuring (Hydrogenation, Disproportionation, Desorption, Recombination, HDDR) four stages. The essence of the HDDR process is that the rare earth intermetallic compounds absorb hydrogen and decompose, and then in the subsequent forced dehydrogenation process, the disproportionated products compound into the original compound phase with fine grains, so as to achieve the refinement of the material grains, and generate the crystal structure along the C axis of the main phase, so as to prepare magnetic powder with excellent magnetic properties and magnetic anisotropy.

Aichi Steel brings the HDDR anisotropic magnetic powder to the market by using a dynamic HDDR process (d-HDDR) that controls temperature and hydrogen pressure over time, making it easier to achieve anisotropic texture of magnetic powder and to achieve stable industrial production conditions.