Anisotropic magnetic powder and magnet thereof and method of producing same

Abstract

A the magnetically anisotropic magnetic powder having an average particle size of 1-1000 mum and made from a magnetically anisotropic R-TM-B-Ga or R-TM-B-Ga-M alloy having an average crystal grain size of 0.01-0.5 mum, wherein R represents one or more rare earth elements including Y, TM represents Fe which may be partially substituted by Co, B boron, Ga gallium, and M one or more elements selected from the group consisting of Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn. This is useful for anisotropic resin-bonded magnet with high magnetic properties.

What is claimed is:  
     
       1. A magnetically anisotropic magnetic powder of rare earth-iron-boron having improved thermal stability, having an average particle size of 1-1000 μm and made from a magnetically anisotropic R-TM-B-Ga alloy having an average crystal grain size of 0.01-0.5 μm, wherein R represents one or more rare earth elements including Y, TM represents Fe which may be partially substituted by Co, B represents boron and Ga represents gallium, wherein said R-TM-B-Ga alloy comprises 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga, and balance Fe which may be partially substituted by 30 at. % or less of Co, and inevitable impurities. 
     
     
       2. The magnetically anisotropic magnetic powder according to  claim 1 , wherein said R-TM-B-Ga alloy powder consists essentially of 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga, and balance Fe which may be partially substituted by Co, and inevitable impurities. 
     
     
       3. The magnetically anisotropic magnetic powder according to  claim 1 , having a residual magnetic flux density of 8 KG or more in the direction of the axis of said magnetic powder along which it is easily magnetizable. 
     
     
       4. The magnetically anisotropic magnetic powder according to  claim 1 , wherein said anisotropic R-TM-B-Ga alloy powder is prepared by pressing flakes obtained from a melt having the composition of R-TM-B-Ga by a rapid quenching method to provide a pressed magnet, giving it anisotropy by plastic deformation and then pulverizing it. 
     
     
       5. The magnetically anisotropic magnetic powder according to  claim 4 , wherein the anisotropy is given by die upsetting while heating. 
     
     
       6. The magnetically anisotropic magnetic powder according to  claim 1 , wherein the ratio of the average dimension (c) of said crystal grains measured perpendicular to their C axes to the average dimension (a) thereof measured parallel to their C axes is 2 or more. 
     
     
       7. A magnetically anisotropic pressed powder magnet having improved thermal stability, made of magnetically anisotropic R-TM-B-Ga alloy having an average crystal grain size of 0.01-0.5 μm wherein R consisting essentially of Nd part of which may be substituted with Dy, TM represents Fe which may be partially substituted by Co, B represents boron, and Ga represents gallium, said magnetically anisotropic R-TM-B-Ga alloy having an axis of easy magnetization, wherein said R-TM-B-Ga alloy comprises 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga and balance Fe which may be partially substituted by  30 at %  atomic %  or less of Co, and inevitable impurities. 
     
     
       8. The magnetically anisotropic pressed powder magnet according to  claim 7 , wherein said R-TM-B-Ga alloy consists essentially of 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga and balance Fe which may be partially substituted by Co, and inevitable impurities. 
     
     
       9. The magnetically anisotropic pressed powder magnet according to  claim 7 , wherein said anisotropic R-TM-B-Ga alloy powder is  is powder prepared by pressing flakes obtained from a melt having the composition of R-TM-B-Ga by a rapid quenching method to provide a pressed magnet, giving it anisotropy by plastic deformation and then pulverizing it. 
     
     
       10. The magnetically anisotropic pressed powder magnet according to  claim 9 , wherein the anisotropy is given by die upsetting while heating. 
     
     
       11. A magnetically anisotropic resin-bonded magnet of rare earth-iron-boron having improved thermal stability composed of 15-40 volume % of a resin binder and balance R-TM-B-Ga alloy powder having an average crystal grain size of 0.01-0.5 μm, wherein R represents one or more rare earth elements including Y, TM represents Fe which may be partially substituted by Co, B represents boron and Ga represents gallium, said magnetically anisotropic R-TM-B-Ga alloy having an axis of easy magnetization, wherein said R-TM-B-Ga alloy comprises 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga, and balance Fe which may be partially substituted by 30 at % or less of Co, and inevitable impurities. 
     
     
       12. The magnetically anisotropic resin-bonded magnet according to  claim 11 , wherein said R-TM-B-Ga alloy consists essentially of 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga and balance Fe which may be partially substituted by Co, and inevitable impurities. 
     
     
       13. The magnetically anisotropic resin-bonded magnet according to  claim 11 , wherein said anisotropic R-TM-B-Ga alloy powder is prepared by rapidly quenching a melt of the R-TM-B-Ga composition to form flakes which are pressed and then subjected to plastic deformation to have anisotropy and then pulverized. 
     
     
       14. The magnetically anisotropic resin-bonded magnet according to  claim 13 , wherein the anisotropy is given by die upsetting while heating. 
     
     
       15. A magnetically anisotropic magnetic powder of rare earth-iron-boron having improved thermal stability, the powder having an average particle size of 1-1000 μm, and composed of an R-TM-B-Ga-M alloy powder having an average crystal grain size of 0.01-0.5 μm, wherein R represents one or more rare earth elements including Y, TM represents Fe which may be partially substituted by Co, B represents boron, Ga represents gallium and M represents one or more elements selected from the group consisting of Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn, wherein said R-TM-B-Ga-M alloy comprises 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga, 3 atomic % or less of M and balance Fe which may be partially substituted by 30 at % or less of Co, and inevitable impurities. 
     
     
       16. The magnetically anisotropic magnetic powder according to  claim 15 , wherein said R-TM-B-Ga-M alloy consists essentially of 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga, 3 atomic % or less of M and balance Fe which may be partially substituted by Co, and inevitable impurities. 
     
     
       17. The magnetically anisotropic magnetic powder according to  claim 16 , wherein the residual magnetic flux density thereof in the direction of easy magnetization axis is 8 KG or more. 
     
     
       18. The magnetically anisotropic magnetic powder according to  claim 15 , wherein said anisotropic R-TM-B-Ga-M alloy powder is prepared by rapidly quenching a melt of the R-TM-B-Ga-M composition to form flakes which are pressed and then subjected to plastic deformation to have anisotropy and then pulverized. 
     
     
       19. The magnetically anisotropic magnetic powder according to  claim 18 , wherein the anisotropy is given by die upsetting while heating. 
     
     
       20. The magnetically anisotropic magnetic powder according to  claim 15 , wherein the ratio of an average dimension (c) of said crystal grains measured perpendicular to their C axes to an average dimension (a) thereof measured parallel to their C axes is 2 or more. 
     
     
       21. The magnetically anisotropic magnetic powder according to  claim 20 , wherein said R-TM-B-Ga-M alloy powder consists essentially of 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga, 3 atomic % or less of M and balance Fe which may be partially substituted by Co, and inevitable impurities. 
     
     
       22. The magnetically anisotropic magnetic powder according to  claim 21 , wherein the residual magnetic flux density thereof in the direction of easy magnetization axis is 8 KG or more. 
     
     
       23. A magnetically anisotropic pressed powder magnet having improved thermal stability made of magnetically anisotropic R-TM-B-Ga-M alloy having an average crystal grain size of 0.01-0.5 μm, wherein R consisting essentially of Nd part of which may be substituted by Dy, TM represents Fe which may be partially substituted by Co, B represents boron, Ga represents gallium, and M represents one or more elements selected from the group consisting of Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn, said magnetically anisotropic R-TM-B-Ga-M alloy having an axis of easy magnetization, wherein said R-TM-B-Ga-M alloy comprises 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga, 3 atomic % or less of M and balance Fe which may be partially substituted by  30 at %  atomic %  or less of Co, and inevitable impurities. 
     
     
       24. The magnetically anisotropic pressed powder magnet according to  claim 23 , wherein said R-TM-B-Ga-M alloy consists essentially of 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga, 3 atomic % or less of M and balance Fe which may be partially substituted by Co, and inevitable impurities. 
     
     
       25. The magnetically anisotropic pressed powder magnet according to  claim 23 , wherein said anisotropic R-TM-B-Ga-M alloy powder is  is powder prepared by rapidly quenching a melt of the R-TM-B-Ga-M composition to form flakes which are pressed and then subjected to plastic deformation to have anisotropy and then pulverized. 
     
     
       26. The magnetically anisotropic pressed powder magnet according to  claim 25 , wherein the anisotropy is given by die upsetting while heating. 
     
     
       27. A magnetically anisotropic resin-bonded magnet of rare earth-iron-boron having improved thermal stability composed of 15-40 volume % of a resin binder and balance R-TM-B-Ga-M alloy powder having an average crystal grain size of 0.01-0.5 μm, wherein R represents one or more rare earth elements including Y, TM represents Fe which may be partially substituted by Co, B represents boron, Ga represents gallium, and M represents one or more elements selected from the group consisting of Nb, W, V, Ta, Mo, Si, Al, Zr, Hf, P, C and Zn, said magnetically anisotropic R-TM-B-Ga-M alloy powder having an axis of easy magnetization, wherein said R-TM-B-Ga-M alloy powder comprises 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga, 3 atomic % or less of M and balance Fe which may be partially substituted by  30 at %  atomic %  of Co, and inevitable impurities. 
     
     
       28. The magnetically anisotropic resin-bonded magnet according to  claim 27 , wherein said R-TM-B-Ga-M alloy powder consists essentially of 11-18 atomic % of R, 4-11 atomic % of B, 5 atomic % or less of Ga, 3 atomic % or less of M and balance Fe which may be partially substituted by Co, and inevitable impurities. 
     
     
       29. The magnetically anisotropic resin-bonded magnet according to  claim 27 , wherein said anisotropic R-TM-B-Ga-M alloy powder is prepared by rapidly quenching a melt of the R-TM-B-Ga-M composition to form flakes which are pressed and then subjected to plastic deformation to have anisotropy and then pulverized. 
     
     
       30. The magnetically anisotropic resin-bonded magnet according to  claim 29 , wherein the anisotropy is given by die upsetting while heating. 
     
     
       31. The magnetically anisotropic magnetic powder according to  claim 1 , wherein Ga is 0.01-3 atomic %. 
     
     
       32. The magnetically anisotropic pressed powder magnet according to  claim 7 , wherein Ga is 0.01-3 atomic %. 
     
     
       33. The magnetically anisotropic resin-bonded magnet according to  claim 11 , wherein Ga is 0.01-3 atomic %. 
     
     
       34. The magnetically anisotropic magnetic powder according to  claim 15 , wherein Ga is 0.01-3 atomic %. 
     
     
       35. The magnetically anisotropic pressed powder magnet according to  claim 23 , wherein Ga is 0.01-3 atomic %. 
     
     
       36. The magnetically anisotropic resin-bonded magnet according to  claim 27 , wherein Ga is 0.01-3 atomic %. 
     
     
       37. The magnetically anisotropic magnetic powder according to  claim 1 , wherein R consists of Nd part of which may be substituted with Dy. 
     
     
       38. The magnetically anisotropic pressed powder magnet according to  claim 7 , wherein R consists of Nd part of which may be substituted with Dy. 
     
     
       39. The magnetically anisotropic resin-bonded magnet according to  claim 11 , wherein R consists of Nd part of which may be substituted with Dy. 
     
     
       40. The magnetically anisotropic magnetic powder according to  claim 15 , wherein R consists of Nd part of which may be substituted with Dy. 
     
     
       41. The magnetically anisotropic pressed powder magnet according to  claim 23 , wherein R consists of Nd part of which may be substituted with Dy. 
     
     
       42. The magnetically anisotropic resin-bonded magnet according to  claim 27 , wherein R consists of Nd part of which may be substituted with Dy.