Rare earth sintered magnet and method for producing same

A sintered rare-earth magnet comprising an Nd2Fe14B type crystalline phase as its main phase and Al as an additive;

• wherein
• the rare-earth magnet includes at least one light rare-earth element LR selected from the group consisting of yttrium and the rare-earth elements other than Dy, Ho and Tb, and at least one heavy rare-earth element HR selected from the group consisting of Dy, Ho and Tb;
• and
• the mole fractions α1, α2 and β of the light and heavy rare-earth elements LR and HR and Al satisfy the inequalities
• 25≦α1+α2≦40 mass %;
• 0<α2≦40 mass %;
• β>0.20 mass %;
• and
• 0.04≦β/α2≦0.12.

A method for producing a sintered rare-earth magnet, the method comprising the steps of:

• providing a rapidly solidified alloy that includes at least one light rare-earth element LR, at least one heavy rare-earth element HR and Al as an additive, the at least one light rare-earth element LR being selected from the group consisting of yttrium and the rare-earth elements other than Dy, Ho and Tb, the at least one heavy rare-earth element HR being selected from the group consisting of Dy, Ho and Tb, the mole fractions α1, α2 and β of the light and heavy rare-earth elements LR and HR and Al satisfying the inequalities 25≦α1+α2≦40 mass %, 0≦α2≦40 mass %, β>0.20 mass %, and 0.04≦β/α2≦0.12.
• pulverizing the rapidly solidified alloy to make a powder;
• compacting the powder under a magnetic field to make a compact;
• and
• sintering the compact, thereby obtaining a sintered rare-earth magnet including an Nd2Fe14B type crystalline phase as its main phase.