| 摘要 |
PROBLEM TO BE SOLVED: To inhibit the oxidization of rare-earth elements being contained in an R-T-B rare-earth magnet alloy and to reduce the B-rich phase of a rake- earth magnet while an increase in the coarseness of the R2 T14 B main phase of the magnet is suppressed by a method wherein the magnet has a composition consisting of R, B, Co, M, oxygen, nitrogen and carbon, which respectively have a specified wt.%, with the balance of Fe, the coersive force of the magnet at a specified temperature is specified and at the same time, the area ratio of the B-rich phase is specified. SOLUTION: A rare-earth magnet has a composition consisting of 27.0 to 31.0 wt.% of R (The R is one kind of the element or more than two kinds of the elements out of rare-earth elements including Y.), 0.8 to 1.02 wt.% of B, 0.5 to 50 wt.% of Co, 0.01 to 1.0 wt.% of M (The M is one kind of the element or more than two kinds of the elements out of Ga, Al and Cu), 0.25 wt.% or lower of oxygen, 0.02 to 0.15 wt.% of nitrogen and 0.15 wt.% or lower of carbon with the balance of Fe. Moreover, the coercive force of the magnet at 20 deg.C is 13 kOe or higher and at the same time, the area ratio of the B-rich phase of the magnet is 0 to 0.5% and the area ratio of main phase crystal grains of a grain diameter of 16 μm or wider is 10% or lower. |
