Ramp;#x2014;Feamp;#x2014;B sintered magnet and making method

摘要

The invention provides an R—Fe—B sintered magnet consisting essentially of 12-17 at % of Nd, Pr and R, 0.1-3 at % of M₁, 0.05-0.5 at % of M₂, 4.8+2*m to 5.9+2*m at % of B, and the balance of Fe, containing R₂(Fe,(Co))₁₄B intermetallic compound as a main phase, and having a core/shell structure that the main phase is covered with grain boundary phases. The sintered magnet exhibits a coercivity of at least 10 kOe despite a low or nil content of Dy, Tb and Ho.