Rare earth magnet, process for producing same, and motor using rare earth magnet

1. A rare earth magnet comprising:

rare earth magnet particles; and

a rare earth oxide which is present among the rare earth magnet particles, the rare earth oxide being represented by the following general formula (I):

R 2x R′ 2(1−x) O 3   (I)

where each of R and R′ is one element selected from the group consisting of yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu), and 0<x<1,

wherein R and R′ refer to different elements and

wherein the rare earth magnet particles and the rare earth oxide are physically or chemically bound together.

2. A rare earth magnet as claimed in claim 1 , where each of R and R′ is one element selected from the group consisting of yttrium (Y), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu).

3. A rare earth magnet as claimed in claim 1 , wherein R is neodymium (Nd), and R′ is one element selected from the group consisting of terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu).

4. A rare earth magnet as claimed in claim 3 , wherein R′ is terbium (Tb), and 0<x<0.83.

5. A rare earth magnet as claimed in claim 3 , wherein R′ is dysprosium (Dy), and 0<x<0.86.

6. A rare earth magnet as claimed in claim 3 , wherein R′ is holmium (Ho), and 0<x<0.86.

7. A rare earth magnet as claimed in claim 3 , wherein R′ is erbium (Er), and 0<x<0.88.

8. A rare earth magnet as claimed in claim 3 , wherein R′ is thulium (Tm), and 0<x<0.89.

9. A rare earth magnet as claimed in claim 3 , wherein R′ is ytterbium (Yb), and 0<x<0.90.

10. A rare earth magnet as claimed in claim 3 , wherein R′ is lutetium (Lu), and 0<x<0.91.

11. A rare earth magnet as claimed in claim 1 , wherein the rare earth magnet particles have a particle size ranging from 1 to 500 μm.

12. A rare earth magnet as claimed in claim 1 , wherein the rare earth magnet is a Nd—Fe—B based magnet.

13. A rare earth magnet as claimed in claim 1 , wherein the rare earth magnet is an anisotropic magnet.

14. A process for producing a rare earth magnet, comprising:

preparing a mixture containing rare earth magnet powder and rare earth oxide powder whose rare earth oxide is represented by the following general formula (I):

R 2x R′ 2(1−x) O 3   (I)

where each of R and R′ is an element selected from the group consisting of yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu), and 0<x<1;

charging a forming die with the mixture; and

forming the mixture;

wherein R and R′ refer to different elements and

wherein the step of forming the mixture comprises physically or chemically bonding together the rare earth magnet powder and the rare earth oxide powder.

15. A process as claimed in claim 14 , wherein the rare earth magnet powder is anisotropic rare earth magnet powder, wherein the process further comprises provisionally forming the mixture while carrying out orientation of the rare earth magnet powder in a magnetic field, after the charging the forming die with the mixture and before the forming the mixture.

16. A process as claimed in claim 14 , wherein the forming the mixture is carried out by using a pressure sintering.

17. A motor comprising:

a rare earth magnet including

rare earth magnet particles; and

a rare earth oxide which is present among the rare earth magnet particles, the rare earth oxide being represented by the following general formula (I):

R 2x R′ 2(1−x) O 3   (I)

where each of R and R′ is one element selected from the group consisting of yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb) and lutetium (Lu), and 0<x<1,

wherein R and R′ refer to different elements; and

wherein the rare earth magnet particles and the rare earth oxide are physically or chemically bound together.