R-Fe-B TYPE SINTERED MAGNET AND METHOD FOR MAKING THE SAME

The present invention comprises an M2 boride phase at the trigeminal triple point, and R1.1 Fe4B It does not comprise acompound phase, and the main phase (R, HR) 2 (Fe, (Co))14 B (R is a rare earth element, HR is Dy, Tb or Ho) is coated with an HR rich layer having a thickness of 0.01 to 1.0 μm, and is amorphous and / or 10 nm or less of the microcrystalline (R, HR) -Fe (Co)-M1 phase, or the corresponding (R, HR) -Fe (Co)-M1 phase and R is at least 50 atom% crystalline or 10nm or less of the uncrystalline and amorphous (R, HR) -M Having a core / shell structure coated by a granular phase comprising a phase1, the surface area coating ratio for the scaphoid having an HR rich layer of (R, HR) -Fe (Co) -M1 is at least 50%, and the phase width of the granular phase inserted into the scaphoid phase 2 particles is at least 10 nm, On average It relates to an R-Fe-B based sintered magnet. The magnets of the present invention impart a coercivity of at least 10 kOe in the content of Dy, Tb and Ho.