SINTERED R-Fe-B MAGNET AND METHOD FOR PRODUCTION THEREOF Russian patent published in 2019 - IPC H01F1/57 H01F41/02 B22F3/10 C22C33/02 

FIELD: physics.

SUBSTANCE: present invention relates to a sintered R-Fe-B based magnet and to a method for production thereof. Sintered R-Fe-B magnet consists mainly of 12–17 at. % Nd, Pr and R, 0.1–3 at. % M₁, 0.05–0.5 at. % M₂, 4.8 + 2×m-5.9 + 2×m at. % B and Fe content, contains intermetallic compound R₂(Fe, (Co))₁₄B as the main phase and has a core/shell structure in which the main phase is coated with phases of grain boundaries, containing an amorphous and/or nanocrystalline phase of R-Fe(Co)-M₁ with size of crystals less than 10 nm, consisting mainly of 25–35 at. % R, 2–8 at. % M₁, up to 8 at. % Co and Fe, or R-Fe (Co)-M₁ phase and crystalline or nanocrystalline with particle size less than 10 nm, and amorphous phase RM₁, having at least 50 atomic % R, wherein surface area of coating from phase R-Fe(Co)-M₁ on the main phase is at least 50 %, grain boundary phase width is at least 10 nm and at least 50 nm on average.

EFFECT: invention enables to produce sintered magnet with coercive force at least 10 kOe, in spite of low or zero content of Dy, Tb and Ho.

8 cl, 4 tbl, 5 dwg