A sintered nd - fe - b - magnet and its manufacturing method.

摘要

An Nd-Fe-B sintered magnet which has 0.5 %/°C. or more of temperature-coefficient of coercive force (iHc) and a composition that R=11-18 at % (R is one or more rare-earth elements except for Dy, with the proviso of 80 at % ≦(Nd+Pr)/R≦100 at %), B=6-12 at %, and balance of Fe and Co (with the proviso of Co is 25 at % or less relative to the total of Co and Fe (including 0 % of Co)) and impurities, is improved to have 15 kOe or more of coercive force (iHc) by means of further containing 2-6 at % of V and modifying the minority phase such that B in excess of a stoichiometric composition of R.sub.2 Fe.sub.14 B compound-phase essentially does not form RFe.sub.4 B.sub.4 -compound minority phase but forms a finely dispersed V-T-B compound minority phase (T is fe, and in a case of containing Co, T is Fe and Co).