W-containing R—Fe—B—Cu sintered magnet and quenching alloy

Abstract

The present invention discloses a W-containing RFeBCu serial sintered magnet and quenching alloy. The sintered magnet contains an R.sub.2Fe.sub.14B-type main phase, the R being at least one rare earth element comprising Nd or Pr; the crystal grain boundary of the rare earth magnet contains a W-rich area above 0.004 at % and below 0.26 at %, and the W-rich area accounts for 2.0 vol %11.0 vol % of the sintered magnet. The sintered magnet uses a minor amount of W pinning crystal to segregate the migration of the pinned grain boundary in the crystal grain boundary to effectively prevent abnormal grain growth and obtain significant improvement. The crystal grain boundary of the quenching alloy contains a W-rich area above 0.004 at % and below 0.26 at %, and the W-rich area accounts for at least 50 vol % of the crystal grain boundary.

Claims

1. A W-containing RFeBCu serial sintered magnet, comprising: an R.sub.2Fe.sub.14B-type main phase, the R being at least one rare earth element comprising Nd or Pr, wherein a crystal grain boundary of the W-containing RFeBCu serial sintered magnet comprises a W-rich area with W content above 0.004 at % and below 0.26 at %, the W-rich area distributed with a uniform dispersion in the crystal grain boundary, wherein in the raw material of the W-containing RFeBCu serial sintered magnet, R content is 12 at % to 15.2 at %, B content is 5 at % to 8 at %, W content is 0.0005 at % to 0.03 at %, Cu content is 0.05 at % to 1.2 at %, X content is below 5.0 at %, the X being selected from at least one element of Al, Si, Ga, Sn, Ge, Ag, Au, Bi, Mn, Nb, Zr or Cr, the total content of Nb and Zr is below 0.20 at % when the X comprises at least one of Nb or Zr, Co content is 0 at % to 20 at %, and the balance is Fe and inevitable impurities, and wherein O content of the W-containing RFeBCu serial sintered magnet is 0.1 at % to 1.0 at %.

2. The W-containing RFeBCu serial sintered magnet according to claim 1, wherein the content of X is below 2.0 at %.

3. The W-containing RFeBCu serial sintered magnet according to claim 2, wherein the content of W is 0.005 at % to 0.03 at %.

4. The W-containing RFeBCu serial sintered magnet according to claim 1, wherein the W-containing RFeBCu serial sintered magnet is manufactured by the following steps: producing an alloy for the W-containing RFeBCu serial sintered magnet by casting a molten raw material with a composition of the W-containing RFeBCu serial sintered magnet at a quenching speed of 10.sup.2 C./s to 10.sup.4 C./s; producing a fine powder by firstly coarsely crushing and secondly finely crushing the alloy for the W-containing RFeBCu serial sintered magnet; obtaining a compact by a magnetic field compacting method; and sintering the compact in vacuum or inert gas at a temperature of 900 C. to 1100 C. to obtain the W-containing RFeBCu serial sintered magnet.

5. The W-containing RFeBCu serial sintered magnet according to claim 1, wherein the content of B is 5 at % to 6.5 at %.

6. The W-containing RFeBCu serial sintered magnet according to claim 1, wherein the W-containing RFeBCu serial sintered magnet has a content of Al of 0.8 at % to 2.0 at %.

7. The W-containing RFeBCu serial sintered magnet according to claim 4, wherein: the coarsely crushing comprises hydrogen decrepitating the alloy for the W-containing RFeBCu serial sintered magnet to obtain a coarse powder, the finely crushing comprises jet milling the coarse powder, and the W-containing RFeBCu serial sintered magnet is further manufactured by the following step: removing at least one part of the fine powder with a particle size of smaller than 1.0 m after the finely crushing, so that the fine powder which has a particle size smaller than 1.0 m is reduced to below 10% of total powder by volume.

8. The W-containing RFeBCu serial sintered magnet according to claim 1, wherein the W-containing RFeBCu serial sintered magnet is manufactured by the following step: treating the W-containing RFeBCu serial sintered magnet by RH grain boundary diffusion, the RH being selected from at least one of Dy or Tb.

9. The W-containing RFeBCu serial sintered magnet according to claim 8, wherein the W-containing RFeBCu serial sintered magnet is manufactured by the following step: aging treating the W-containing RFeBCu serial sintered magnet at a temperature of 400 C. to 650 C.

10. The W-containing RFeBCu serial sintered magnet according to claim 1, wherein the content of O of the W-containing RFeBCu serial sintered magnet is 0.1 at % to 0.5 at %.

11. The W-containing RFeBCu serial sintered magnet according to claim 1, wherein the W-containing RFeBCu serial sintered magnet has a content of Ga of 0.05 at % to 0.8 at %.

12. The W-containing RFeBCu serial sintered magnet according to claim 1, wherein the W is comprised in the inevitable impurities.

13. The W-containing RFeBCu serial sintered magnet according to claim 1, wherein the W-rich area accounts for at least 50 vol % of the crystal grain boundary.

14. A quenching alloy for W-containing RFeBCu serial sintered magnet, wherein the quenching alloy comprises: a W-rich area with W content above 0.004 at % and below 0.26 at %, the W-rich area distributed in a crystal grain boundary, and accounting for at least 50 vol % of the crystal grain boundary, wherein in the raw material of the W-containing RFeBCu serial sintered magnet, R content is 12 at % to 15.2 at %, B content is 5 at % to 8 at %, W content is 0.0005 at % to 0.03 at %, Cu content is 0.05 at % to 1.2 at %, X content is below 5.0 at %, the X being selected from at least one element of Al, Si, Ga, Sn, Ge, Ag, Au, Bi, Mn, Nb, Zr or Cr, the total content of Nb and Zr is below 0.20 at % when the X comprises at least one of Nb or Zr, Co content is 0 at % to 20 at %, and the balance is Fe and inevitable impurities, and wherein O content of the W-containing RFeBCu serial sintered magnet is 0.1 at % to 1.0 at %.

15. The quenching alloy for W-containing RFeBCu serial sintered magnet according to claim 14, wherein the content of X is below 2.0 at %.

16. The quenching alloy for W-containing RFeBCu serial sintered magnet according to claim 14, wherein the content of W is 0.005 at % to 0.03 at %.

17. The quenching alloy for W-containing RFeBCu serial sintered magnet according to claim 14, wherein the content of B is 5 at % to 6.5 at %.

18. A W-containing RFeBCu serial sintered magnet, comprising: an R.sub.2Fe.sub.14B-type main phase, the R being at least one rare earth element comprising Nd or Pr, wherein a crystal grain boundary of the W-containing RFeBCu serial sintered magnet comprises a W-rich area with W content above 0.004 at % and below 0.26 at %, the W-rich area distributed in the crystal grain boundary, wherein in the raw material of the W-containing RFeBCu serial sintered magnet, R content is 12 at % to 15.2 at %, B content is 5 at % to 8 at %, W content is 0.0005 at % to 0.03 at %, Cu content is 0.05 at % to 1.2 at %, X content is below 5.0 at %, the X being selected from at least one element of Al, Si, Ga, Sn, Ge, Ag, Au, Bi, Mn, Nb, Zr or Cr, the total content of Nb and Zr is below 0.20 at % when the X comprises at least one of Nb or Zr, Co content is 0 at % to 20 at %, and the balance is Fe and inevitable impurities, and wherein O content of the W-containing RFeBCu serial sintered magnet is 0.1 at % to 1.0 at %.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 schematically illustrates the principle of the pinning effect of W to the grain boundary migration.

(2) FIG. 2 illustrates an EPMA detecting result of a quenching alloy sheet of embodiment 3 of embodiment I.

(3) FIG. 3 illustrates an EPMA detecting result of a sintered magnet of embodiment 3 of embodiment I.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(4) The present invention will be further described with the embodiments.

(5) The definitions of BHH, magnetic property evaluation process and AGG determination are as follows:

(6) BHH is the sum of (BH) max and Hcj, which is one of the evaluation standards of the comprehensive property of the magnet.

(7) Magnetic property evaluation process: testing the sintered magnet by NIM-10000H type nondestructive testing system for BH large rare earth permanent magnet from China Jiliang University.

(8) AGG determination: polishing the sintered magnet in a direction perpendicular to its alignment direction, the average amount of AGG comprised in each 1 cm.sup.2 are determined, the AGG stated by the present invention has a grain size exceeding 40 m.

(9) The detecting limit detected with FE-EPMA stated by each embodiment is around 100 ppm; the detecting conditions are as follows:

(10) TABLE-US-00002 CH spectro- accel- analyzing meter analysis erating probe standard element crystal channel line voltage current sample Cu LiFH CH-3 L 20 kv 50 nA Cu simple substance Nd LiFH CH-3 L 20 kv 50 nA NdP.sub.5O.sub.14 W LiFH CH-4 L 20 kv 50 nA W simple substance

(11) The highest resolution of FE-EPMA reaches 3 nm, the resolution may also reach 50 nm under the above stated detecting conditions.

Embodiment I

(12) Raw material preparing process: preparing Nd and Dy respectively with 99.5% purity, industrial FeB, industrial pure Fe, Co with 99.9% purity, Cu and Al respectively with 99.5% purity, and W with 99.999% purity; being counted in atomic percent at %.

(13) In order to precisely control the using proportioning of W, the content of W of the Nd, Dy, Fe, B, Al, Cu and Co used in the embodiment is under the detecting limit of the existing devices, the resource of W is from an extra added W metal.

(14) The contents of each element are shown in TABLE 2:

(15) TABLE-US-00003 TABLE 2 Proportioning of each element (at %) No. Nd Dy B W Al Cu Co Fe 1 13.5 0.5 6 3*10.sup.4 1 0.1 1.8 remainder 2 13.5 0.5 6 5*10.sup.4 1 0.1 1.8 remainder 3 13.5 0.5 6 0.002 1 0.1 1.8 remainder 4 13.5 0.5 6 0.01 1 0.1 1.8 remainder 5 13.5 0.5 6 0.02 1 0.1 1.8 remainder 6 13.5 0.5 6 0.03 1 0.1 1.8 remainder 7 13.5 0.5 6 0.05 1 0.1 1.8 remainder

(16) Preparing 100 Kg raw material of each sequence number group by respective weighing in accordance with TABLE 2.

(17) Melting process: placing the prepared raw material into an aluminum oxide made crucible at a time, performing a vacuum melting in an intermediate frequency vacuum induction melting furnace in 10.sup.2 Pa vacuum and below 1500 C.

(18) Casting process: after the process of vacuum melting, filling Ar gas into the melting furnace so that the Ar pressure would reach 50000 Pa, then obtaining a quenching alloy by being casted by single roller quenching method at a quenching speed of 10.sup.2 C./s10.sup.4 C./s, thermal preservating the quenching alloy at 600 C. for 60 minutes, and then being cooled to room temperature.

(19) Detecting the compound of Cu, Nd and W of the quenching alloy manufactured according to embodiment 3 with FE-EPMA (Field emission-electron probe micro-analyzer) [Japanese electronic kabushiki gaisya (JEOL), 8530F], the results are shown in FIG. 2, which may be observed that, W is distributed in R-rich phase with a high dispersity.

(20) Detecting the quenching alloy sheets with FE-EPMA, the W-rich region is distributed in the crystal grain boundary with a uniform dispersity, and occupies at least 50 vol % of the alloy crystal grain boundary, wherein, the W-rich region means a region with the content of W above 0.004 at % and below 0.26 at %.

(21) Hydrogen decrepitation process: at room temperature, vacuum pumping the hydrogen decrepitation furnace placed with the alloy, then filling hydrogen with 99.5% purity into the furnace until the pressure reaches 0.1 MPa, after the alloy being placed for 2 hours, vacuum pumping and heating at the same time, performing the vacuum pumping at 500 C. for 2 hours, then being cooled, and the powder treated after hydrogen decrepitation process being taken out.

(22) Fine crushing process: performing jet milling to a sample in the crushing room under a pressure of 0.4 MPa and in the atmosphere with oxidizing gas below 100 ppm, then obtaining an average particle size of 4.5 m of fine powder. The oxidizing gas means oxygen or water.

(23) Adopting a classifier to classify the partial fine powder (occupies 30% of the total weight of the fine powder) treated after the fine crushing process, removing the powder particle with a particle size smaller than 1.0 m, then mixing the classified fine powder and the remaining un-classified fine powder. The powder with a particle size smaller than 1.0 m is reduced to below 10% of total powder by volume in the mixed fine powder.

(24) Methyl caprylate is added into the powder treated after jet milling, the additive amount is 0.2% of the mixed powder by weight, further the mixture is comprehensively mixed by a V-type mixer.

(25) Compacting process under a magnetic field: a transversed type magnetic field molder being used, compacting the powder added with methyl caprylate in once to form a cube with sides of 25 mm in an orientation field of 1.8 T and under a compacting pressure of 0.4 ton/cm.sup.2, then demagnetizing the once-forming cube in a 0.2 T magnetic field.

(26) The once-forming compact is sealed so as not to expose to air, the compact is secondly compacted by a secondary compact machine (isostatic pressing compacting machine) under a pressure of 1.4 ton/cm.sup.2.

(27) Sintering process: moving each of the compact to the sintering furnace, firstly sintering in a vacuum of 10.sup.3 Pa and respectively maintained for 2 hours at 200 C. and for 2 hours at 800 C., then sintering for 2 hours at 1030 C., after that filling Ar gas into the sintering furnace so that the Ar pressure would reach 0.1 MPa, then being cooled to room temperature.

(28) Heat treatment process: annealing the sintered magnet for 1 hour at 460 C. in the atmosphere of high purity Ar gas, then being cooled to room temperature and taken out.

(29) Machining process: machining the sintered magnet after heat treatment as a magnet with 15 mm diameter and 5 mm thickness, the 5 mm direction being the orientation direction of the magnetic field.

(30) Directly testing the sintered magnet manufactured according to the embodiments 17, and the magnetic property is evaluated. The evaluation results of the magnets of the embodiments are shown in TABLE 3 and TABLE 4.

(31) TABLE-US-00004 TABLE 3 Evaluation of the microstructure of the embodiments Average amount of W in the Ratio of W- grain boundary rich phase amor- iso- number phase in the magnet WB.sub.2 phous tropic of No. (at %) (vol %) phase phase phase AGG 1 0.002 4.8 no no no 23 2 0.004 5.0 no no no 2 3 0.018 7.4 no no no 1 4 0.090 9.5 no no no 0 5 0.168 9.8 no no no 0 6 0.255 11.0 no no no 0 7 0.440 13.2 yes yes yes 0

(32) The amorphous phase and isotropic phase of TABLE 3 investigate the amorphous phase and isotropic phase of the alloy.

(33) The W-rich phase of TABLE 3 is a region with W content above 0.004 at % and below 0.26 at %.

(34) TABLE-US-00005 TABLE 4 Magnetic property evaluation of the embodiments Br Hcj SQ (BH) max No. (kGs) (kOe) (%) (MGOe) BHH 1 12.84 9.43 78.43 36.34 45.77 2 14.22 16.71 96.74 47.23 63.94 3 14.16 17.23 98.96 46.78 64.01 4 14.12 17.65 99.93 46.57 64.22 5 14.06 17.79 99.95 46.76 64.55 6 14.01 17.56 98.84 46.14 63.7 7 13.16 13.28 94.56 39.86 53.14

(35) Through the manufacturing process, special attention is paid to the control of the contents of O, C and N, and the contents of the three elements O, C, and N are respectively controlled to 0.10.5 at %, below 0.3 at % and below 0.1 at %.

(36) We may draw a conclusion that, in the present invention, when the content of W in the magnet is below 0.0005 at %, the pinning effect is hardly effective as the content of W is too low, and the existing of Cu in the raw material may easily causes AGG, and reduces SQ and Hcj, oppositely, when the content of W exceeds 0.03 at %, a part of WB.sub.2 phase may be generated, which reduces the squareness and magnetic property, furthermore, the amorphous phase and the isotropic phase may be generated in the obtained quenching alloy and which sharply reduces the magnetic property.

(37) Detecting the compound of Cu, Nd and W of the quenching alloy manufactured according to embodiment 3 with FE-EPMA (Field emission-electron probe micro-analyzer) [Japanese electronic kabushiki gaisya (JEOL), 8530F], the results are shown in FIG. 3, which may be observed that, W is distributed with a high dispersity and performs a uniform pinning effect to the migration of the grain boundary, and the formation of AGG is prevented.

(38) Similarly, detecting embodiment 2, 4, 5 and 6 with FE-EPMA, which also may be observed that, W performs a uniform pinning effect to the migration of the grain boundary with a high dispersity, and the formation of AGG is prevented.

Embodiment II

(39) Raw material preparing process: preparing Nd, Pr and Tb respectively with 99.9% purity, B with 99.9% purity, Fe with 99.9% purity, W with 99.999% purity, and Cu and Al respectively with 99.5% purity; being counted in atomic percent at %.

(40) In order to precisely control the using proportioning of W, the content of W of the Nd, Pr, Tb, Fe, B, Al and Cu used in the embodiment is under the detecting limit of the existing devices, the resource of W is from an extra added W metal.

(41) The contents of each element are shown in TABLE 5:

(42) TABLE-US-00006 TABLE 5 Proportioning of each element (at %) No. Nd Pr Tb B W Al Cu Fe 1 9.7 3 0.3 5 0.01 0.4 0.03 remainder 2 9.7 3 0.3 5 0.01 0.4 0.05 remainder 3 9.7 3 0.3 5 0.01 0.4 0.1 remainder 4 9.7 3 0.3 5 0.01 0.4 0.3 remainder 5 9.7 3 0.3 5 0.01 0.4 0.5 remainder 6 9.7 3 0.3 5 0.01 0.4 0.8 remainder 7 9.7 3 0.3 5 0.01 0.4 1.2 remainder 8 9.7 3 0.3 5 0.01 0.4 1.5 remainder

(43) Preparing 100 Kg raw material of each sequence number group by respective weighing in accordance with TABLE 5.

(44) Melting process: placing the prepared raw material into an aluminum oxide made crucible at a time, performing a vacuum melting in an intermediate frequency vacuum induction melting furnace in 10.sup.2 Pa vacuum and below 1500 C.

(45) Casting process: after the process of vacuum melting, filling Ar gas into the melting furnace so that the Ar pressure would reach 30000 Pa, then obtaining a quenching alloy by being casted by single roller quenching method at a quenching speed of 10.sup.2 C./s10.sup.4 C./s, thermal preservation treating the quenching alloy at 600 C. for 60 minutes, and then being cooled to room temperature.

(46) Detecting the quenching alloy sheets of embodiments 27 with FE-EPMA, the W-rich region is distributed in the crystal grain boundary with a uniform dispersity, and occupies at least 50 vol % of the alloy crystal grain boundary, wherein, the W-rich region means a region with the content of W above 0.004 at % and below 0.26 at %.

(47) Hydrogen decrepitation process: at room temperature, vacuum pumping the hydrogen decrepitation furnace placed with the alloy, then filling hydrogen with 99.5% purity into the furnace until the pressure reach 0.1 MPa, after the alloy being placed for 125 minutes, vacuum pumping and heating at the same time, performing the vacuum pumping at 500 C. for 2 hours, then being cooled, and the powder treated after hydrogen decrepitation process being taken out.

(48) Fine crushing process: performing jet milling to a sample in the crushing room under a pressure of 0.41 MPa and in the atmosphere of oxidizing gas below 100 ppm, then obtaining an average particle size of 4.30 m of fine powder. The oxidizing gas means oxygen or water.

(49) Methyl caprylate is added into the powder treated after jet milling, the additive amount is 0.25% of the mixed powder by weight, further the mixture is comprehensively mixed by a V-type mixer.

(50) Compacting process under a magnetic field: a transversed type magnetic field molder being used, compacting the powder added with methyl caprylate in once to form a cube with sides of 25 mm in an orientation field of 1.8 T and under a compacting pressure of 0.3 ton/cm.sup.2, then demagnetizing the once-forming cube in a 0.2 T magnetic field.

(51) The once-forming compact is sealed so as not to expose to air, the compact is secondly compacted by a secondary compact machine (isostatic pressing compacting machine) under a pressure of 1.0 ton/cm.sup.2.

(52) Sintering process: moving each of the compact to the sintering furnace, firstly sintering in a vacuum of 10.sup.3 Pa and respectively maintained for 3 hours at 200 C. and for 3 hours at 800 C., then sintering for 2 hours at 1020 C., after that filling Ar gas into the sintering furnace so that the Ar pressure would reach 0.1 MPa, then being cooled to room temperature.

(53) Heat treatment process: annealing the sintered magnet for 1 hour at 620 C. in the atmosphere of high purity Ar gas, then being cooled to room temperature and taken out.

(54) Machining process: machining the sintered magnet after heat treatment as a magnet with 15 mm diameter and 5 mm thickness, the 5 mm direction being the orientation direction of the magnetic field.

(55) Directly testing the sintered magnet manufactured according to the embodiments 18, and the magnetic property is evaluated. The evaluation results of the magnets of the embodiments are shown in TABLE 6 and TABLE 7.

(56) TABLE-US-00007 TABLE 6 Evaluation of the microstructure of the embodiments Average amount Ratio of W- of W in the rich phase amor- iso- number grain boundary in the magnet WB.sub.2 phous tropic of No. (at %) (vol %) phase phase phase AGG 1 0.090 10.0 no yes yes 14 2 0.088 10.1 no no no 2 3 0.092 10.0 no no no 1 4 0.092 9.98 no no no 0 5 0.091 9.95 no no no 0 6 0.093 10.0 no no no 0 7 0.092 10.2 no no no 1 8 0.090 10.0 no yes yes 5

(57) The amorphous phase and isotropic phase of TABLE 6 investigate the amorphous phase and isotropic phase of the alloy.

(58) The W-rich phase of TABLE 6 is a region with W content above 0.004 at % and below 0.26 at %.

(59) TABLE-US-00008 TABLE 7 Magnetic property evaluation of the embodiments Br Hcj SQ (BH) max No. (kGs) (kOe) (%) (MGOe) BHH 1 14.14 14.34 89.56 45.32 59.66 2 14.34 18.67 98.02 48.26 66.93 3 14.23 19.23 98.45 47.74 66.97 4 14.17 20.03 99.56 47.28 67.31 5 14.06 20.38 99.67 46.76 67.14 6 14.02 20.68 99.78 46.46 67.14 7 14.01 20.23 99.71 46.32 66.55 8 13.59 16.76 94.23 43.12 59.88

(60) Through the manufacturing process, special attention is paid to the control of the contents of O, C and N, and the contents of the three elements O, C, and N are respectively controlled to 0.10.5 at %, below 0.4 at % and below 0.2 at %.

(61) We may draw a conclusion that, when the content of Cu is below 0.05 at %, the dependency of the heat treatment temperature of the coercivity may be increased, and the magnetic property is reduced, oppositely, when the content of Cu exceeds 1.2 at %, the generating amount of AGG may be increased as the consequence of low melting point phenomenon of Cu, even the pinning effect of W may hardly prevent the mass generation of AGG, indicating that an appropriate range of Cu and W is existed in the magnet with low content of oxygen.

(62) Similarly, detecting embodiment 27 with FE-EPMA [Japanese electronic kabushiki gaisya (JEOL), 8530F], which also may be observed that, W performs a uniform pinning effect to the migration of the grain boundary with a high dispersity, and the formation of AGG is prevented.

Embodiment III

(63) Raw material preparing process: preparing Nd with 99.5% purity, industrial FeB, industrial pure Fe, Co with 99.9% purity, Cu with 99.5% purity and W with 99.999% purity; being counted in atomic percent at %.

(64) In order to precisely control the using proportioning of W, the content of W of the Nd, Fe, B, Cu and Co used in the embodiment is under the detecting limit of the existing devices, the resource of W is from an extra added W metal.

(65) The contents of each element are shown in TABLE 8:

(66) TABLE-US-00009 TABLE 8 Proportioning of each element (at %) Nd B W Cu Co Fe 15 6 0.02 0.2 0.3 remainder

(67) Preparing 700 Kg raw material by weighing in accordance with TABLE 8.

(68) Melting process: placing the prepared raw material into an aluminum oxide made crucible at a time, performing a vacuum melting in an intermediate frequency vacuum induction melting furnace in 10.sup.2 Pa vacuum and below 1500 C.

(69) Casting process: after the process of vacuum melting, filling Ar gas into the melting furnace so that the Ar pressure would reach 50000 Pa, then obtaining a quenching alloy by being casted by single roller quenching method at a quenching speed of 10.sup.2 C./s10.sup.4 C./s, thermal preservation treating the quenching alloy at 600 C. for 60 minutes, and then being cooled to room temperature.

(70) Detecting the quenching alloy sheets of embodiments 2, 3, 4, 5 and 6 with FE-EPMA, the W-rich region is distributed in the crystal grain boundary with a uniform dispersity, and occupies at least 50 vol % of the alloy crystal grain boundary, wherein, the W-rich region means a region with the content of W above 0.004 at % and below 0.26 at %.

(71) Hydrogen decrepitation process: at room temperature, vacuum pumping the hydrogen decrepitation furnace placed with the alloy, then filling hydrogen with 99.5% purity into the furnace until the pressure reach 0.1 MPa, after the alloy being placed for 97 minutes, vacuum pumping and heating at the same time, performing the vacuum pumping at 500 C. for 2 hours, then being cooled, and the powder treated after hydrogen decrepitation process being taken out.

(72) Fine crushing process: dividing the powder treated after the Hydrogen decrepitation process into 7 parts, performing jet milling to each part of the powder in the crushing room under a pressure of 0.42 MPa and in the atmosphere of 103000 ppm of oxidizing gas, then obtaining an average particle size of 4.51 m of fine powder. The oxidizing gas means oxygen or water.

(73) Methyl caprylate is added into the powder treated after jet milling, the additive amount is 0.1% of the mixed powder by weight, further the mixture is comprehensively mixed by a V-type mixer.

(74) Compacting process under a magnetic field: a transversed type magnetic field molder being used, compacting the powder added with methyl caprylate in once to form a cube with sides of 25 mm in an orientation field of 1.8 T and under a compacting pressure of 0.2 ton/cm.sup.2, then demagnetizing the once-forming cube in a 0.2 T magnetic field.

(75) The once-forming compact is sealed so as not to expose to air, the compact is secondly compacted by a secondary compact machine (isostatic pressing compacting machine) under a pressure of 1.4 ton/cm.sup.2.

(76) Sintering process: moving each of the compact to the sintering furnace, firstly sintering in a vacuum of 10.sup.3 Pa and respectively maintained for 2 hours at 200 C. and for 2 hours at 700 C., then sintering for 2 hours at 1020 C., after that filling Ar gas into the sintering furnace so that the Ar pressure would reach 0.1 MPa, then being cooled to room temperature.

(77) Heat treatment process: in the atmosphere of high purity Ar gas, performing a first order annealing for the sintered magnet for 1 hour at 900 C., then performing a second order annealing for 1 hour at 500 C., being cooled to room temperature and taken out.

(78) Machining process: machining the sintered magnet after heat treatment as a magnet with 15 mm diameter and 5 mm thickness, the 5 mm direction being the orientation direction of the magnetic field.

(79) Thermal demagnetization determination: firstly placing the sintered magnet in an environment of 150 C. and thermal preservation for 30 min, then cooling the sintered magnet to room temperature by nature, testing the magnetic flux of the sintered magnet, comparing the testing result with the testing data before heating, and calculating the magnetic flux retention rates before heating and after heating.

(80) Directly testing the sintered magnet manufactured according to the embodiments 17, and the magnetic property is evaluated. The evaluation results of the magnets of the embodiments are shown in TABLE 9 and TABLE 10.

(81) TABLE-US-00010 TABLE 9 Evaluation of the microstructure of the embodiments content of O.sub.2 of content of H.sub.2O of average amount ratio of W-rich the gas of fine the gas of fine of W in the phase of the content of O crushing process crushing process grain boundary magnet WB.sub.2 Number in the magnet No. (ppm) (ppm) (at %) (vol %) phase of AGG (at %) 1 5 5 0.188 10.0 no 9 0.08 2 28 22 0.180 10.1 no 1 0.1 3 52 42 0.185 10.1 no 0 0.3 4 261 86 0.190 10.2 no 0 0.5 5 350 150 0.185 10.0 no 0 0.8 6 1000 250 0.186 10.0 no 1 1 7 2000 1000 0.180 10.1 no 5 1.2

(82) The W-rich phase of TABLE 9 is a region above 0.004 at % and below 0.26 at %.

(83) TABLE-US-00011 TABLE 10 Magnetic property evaluation of the embodiments magnetic flux Br Hcj SQ (BH)max retention rate No. (kGs) (kOe) (%) (MGOe) BHH (%) 1 12.37 8.52 79.5 28.56 37.08 46.8 2 13.24 14.8 98.1 41.26 56.06 0.8 3 13.25 15.1 99.67 41.43 56.53 0.9 4 13.27 16.4 99.78 41.67 58.07 0.9 5 13.31 16.8 99.85 41.87 58.67 12.7 6 13.24 15.8 98.25 41.23 57.03 13.8 7 13.04 13.5 82.45 38.45 51.95 18.3

(84) Through the manufacturing process, special attention is paid to the control of the contents of C and N, and the contents of the two elements C and N are respectively controlled below 0.2 at % and below 0.25 at %.

(85) We may draw a conclusion that, even an appropriate amount of W and Cu is existed, when the content of O of the magnet is below 0.1 at % and exceeds the limit of W pinning effect, the AGG status may happen easily, and therefore the phenomenon of AGG still happens and which sharply reduces the magnetic property. Oppositely, even an appropriate amount of W and Cu is existed, when the content of O of the magnet exceeds 0.1 at %, consequently, the dispersity of the content of oxygen starts getting worse, and a place with many oxygen and the other place with a few oxygen are generated in the magnet, the generation of AGG is increased as the non-uniform, and which reduces coercivity and squareness.

(86) Similarly, detecting embodiment 26 with FE-EPMA [Japanese electronic kabushiki gaisya (JEOL), 8530F], as a detecting result, which also may be observed that, W performs a uniform pinning effect to the migration of the grain boundary with a high dispersity, and the formation of AGG is prevented.

Embodiment IV

(87) Raw material preparing process: preparing Nd and Dy respectively with 99.5% purity, industrial FeB, industrial pure Fe, Co with 99.9% purity, Cu and Al respectively with 99.5% purity, and W with 99.999% purity; being counted in atomic percent at %.

(88) In order to precisely control the using proportioning of W, the content of W of the Nd, Dy, B, Al, Cu, Co and Fe used in the embodiment is under the detecting limit of the existing devices, the resource of W is from an extra added W metal.

(89) The contents are shown in TABLE 11:

(90) TABLE-US-00012 TABLE 11 Proportioning of each element (at %) No. Nd Dy B W Al Cu Co Fe 1 13.5 0.5 5 0.005 1 0.4 1.8 remainder 2 13.5 0.5 5.5 0.005 1 0.4 1.8 remainder 3 13.5 0.5 6.0 0.005 1 0.4 1.8 remainder 4 13.5 0.5 6.5 0.005 1 0.4 1.8 remainder 5 13.5 0.5 7.0 0.005 1 0.4 1.8 remainder 6 13.5 0.5 7.5 0.005 1 0.4 1.8 remainder 7 13.5 0.5 8.0 0.005 1 0.4 1.8 remainder

(91) Preparing 100 Kg raw material of each sequence number group by respective weighing in accordance with TABLE 11.

(92) Melting process: placing the prepared raw material into an aluminum oxide made crucible at a time, performing a vacuum melting in an intermediate frequency vacuum induction melting furnace in 10.sup.2 Pa vacuum and below 1550 C.

(93) Casting process: after the process of vacuum melting, filling Ar gas into the melting furnace so that the Ar pressure would reach 20000 Pa, then obtaining a quenching alloy by being casted by single roller quenching method at a quenching speed of 10.sup.2 C./s10.sup.4 C./s, thermal preservation treating the quenching alloy at 800 C. for 10 minutes, and then being cooled to room temperature.

(94) Detecting the quenching alloy sheets of embodiments 17 with FE-EPMA, the W-rich region is distributed in the crystal grain boundary with a uniform dispersity, and occupies at least 50 vol % of the alloy crystal grain boundary, wherein, the W-rich region means a region with the content of W above 0.004 at % and below 0.26 at %.

(95) Hydrogen decrepitation process: at room temperature, vacuum pumping the hydrogen decrepitation furnace placed with the alloy, then filling hydrogen with 99.5% purity into the furnace until the pressure reach 0.1 MPa, after the alloy being placed for 120 minutes, vacuum pumping and heating at the same time, performing the vacuum pumping at 500 C. for 2 hours, then being cooled, and the powder treated after hydrogen decrepitation process being taken out.

(96) Fine crushing process: performing jet milling to a sample in the crushing room under a pressure of 0.6 MPa and in the atmosphere with oxidizing gas below 100 ppm, then obtaining an average particle size of 4.5 m of fine powder. The oxidizing gas means oxygen or water.

(97) Adopting a classifier to classify the partial fine powder (occupies 30% of the total weight of the fine powder) treated after the fine crushing process, removing the powder particle with a particle size smaller than 1.0 m, then mixing the classified fine powder and the remaining un-classified fine powder. The powder with a particle size smaller than 1.0 m is reduced to below 2% of total powder by volume in the mixed fine powder.

(98) Methyl caprylate is added into the powder treated after jet milling, the additive amount is 0.2% of the mixed powder by weight, further the mixture is comprehensively mixed by a V-type mixer.

(99) Compacting process under a magnetic field: a transversed type magnetic field molder being used, compacting the powder added with methyl caprylate in once to form a cube with sides of 2 5 mm in an orientation field of 1.8 T and under a compacting pressure of 0.2 ton/cm.sup.2, then demagnetizing the once-forming cube in a 0.2 T magnetic field.

(100) The once-forming compact is sealed so as not to expose to air, the compact is secondly compacted by a secondary compact machine (isostatic pressing compacting machine) under a pressure of 1.0 ton/cm.sup.2.

(101) Sintering process: moving each of the compact to the sintering furnace, sintering in a vacuum of 10.sup.3 Pa and respectively maintained for 2 hours at 200 C. and for 2 hours at 800 C., then sintering for 2 hours at 1040 C., after that filling Ar gas into the sintering furnace so that the Ar pressure would reach 0.1 MPa, then being cooled to room temperature.

(102) Heat treatment process: annealing the sintered magnet for 1 hour at 400 C. in the atmosphere of high purity Ar gas, then being cooled to room temperature and taken out.

(103) Machining process: machining the sintered magnet after heat treatment as a magnet with 15 mm diameter and 5 mm thickness, the 5 mm direction being the orientation direction of the magnetic field.

(104) Directly testing the sintered magnet manufactured according to the embodiments 17, and the magnetic property is evaluated. The evaluation results of the magnets of the embodiments are shown in TABLE 12 and TABLE 13.

(105) TABLE-US-00013 TABLE 12 Evaluation of the microstructure of the embodiments Average amount Ratio of W- of W in the rich phase amor- iso- number grain boundary in the magnet WB.sub.2 phous tropic of No. (at %) (vol %) phase phase phase AGG 1 0.040 9.1 no no no 0 2 0.045 9.2 no no no 0 3 0.042 9.1 no no no 0 4 0.040 9.2 no no no 0 5 0.045 9.0 no no no 1 6 0.042 9.1 no no no 1 7 0.045 9.0 yes yes yes 2

(106) The amorphous phase and isotropic phase of TABLE 12 investigate the amorphous phase and isotropic phase of the alloy.

(107) The W-rich phase of TABLE 12 is a region above 0.004 at % and below 0.26 at %.

(108) TABLE-US-00014 TABLE 13 Magnetic property evaluation of the embodiments Br Hcj SQ (BH) max No. (kGs) (kOe) (%) (MGOe) BHH 1 13.85 17.7 99.4 44.8 62.5 2 13.74 17.5 99.62 44.1 61.6 3 13.62 18.2 99.67 43.31 61.51 4 13.5 17.8 99.78 42.5 60.3 5 13.4 16.6 99.85 41.83 58.43 6 13.26 16.6 98.25 41.04 57.64 7 13.14 16.6 98.24 40.32 56.92

(109) Through the manufacturing process, special attention is paid to the control of the contents of O, C and N, and the contents of the three elements O, C, and N are respectively controlled to 0.10.5 at %, below 0.3 at % and below 0.1 at %.

(110) Detecting the embodiments 17 with FE-EPMA (Field emission-electron probe micro-analyzer) [Japanese electronic kabushiki gaisya (JEOL), 8530F], which may be observed that, W is distributed with a high dispersity and performs a uniform pinning effect to the migration of the grain boundary, and the formation of AGG is prevented.

(111) Conclusion: by the analysis of FE-EPMA, when the content of B is above 6.5 at %, a great amount of R(T,B).sub.2 comprising B may be generated in the crystal grain boundary, and when the content of B is 5 at %6.5 at %, R.sub.6T.sub.13X (X=Al, Cu etc.) type phase comprising W is generated, the generation of this phase optimizes the coercivity and squareness and possess a weak magnetism, W is beneficial to the generation of R.sub.6T.sub.13X type phase and improves the stability.

Embodiment V

(112) Raw material preparing process: preparing Nd and Dy respectively with 99.5% purity, industrial FeB, industrial pure Fe, Co with 99.9% purity, Cu and Al respectively with 99.5% purity, and W with 99.999% purity; being counted in atomic percent at %.

(113) In order to precisely control the using proportioning of W, the content of W of the Nd, Dy, B, Al, Cu, Co and Fe used in the embodiment is under the detecting limit of the existing devices, the resource of W is from an extra added W metal.

(114) The contents of each element are shown in TABLE 14:

(115) TABLE-US-00015 TABLE 14 Proportioning of each element (at %) No. Nd Dy B W Al Cu Co Fe 1 13.5 0.5 6.0 0.01 0.1 0.1 1.8 remainder 2 13.5 0.5 6.0 0.01 0.2 0.1 1.8 remainder 3 13.5 0.5 6.0 0.01 0.5 0.1 1.8 remainder 4 13.5 0.5 6.0 0.01 0.8 0.1 1.8 remainder 5 13.5 0.5 6.0 0.01 1.0 0.1 1.8 remainder 6 13.5 0.5 6.0 0.01 1.5 0.1 1.8 remainder 7 13.5 0.5 6.0 0.01 2.0 0.1 1.8 remainder

(116) Preparing 100 Kg raw material of each sequence number group by respective weighing in accordance with TABLE 14.

(117) Melting process: placing the prepared raw material into an aluminum oxide made crucible at a time, performing a vacuum melting in an intermediate frequency vacuum induction melting furnace in 10.sup.2 Pa vacuum and below 1500 C.

(118) Casting process: after the process of vacuum melting, filling Ar gas into the melting furnace so that the Ar pressure would reach 50000 Pa, then obtaining a quenching alloy by being casted by single roller quenching method at a quenching speed of 10.sup.2 C./s10.sup.4 C./s, thermal preservating the quenching alloy at 700 C. for 5 minutes, and then being cooled to room temperature.

(119) Hydrogen decrepitation process: at room temperature, vacuum pumping the hydrogen decrepitation furnace placed with the alloy, then filling hydrogen with 99.5% purity into the furnace until the pressure reach 0.1 MPa, after the alloy being placed for 120 minutes, vacuum pumping and heating at the same time, performing the vacuum pumping at 600 C. for 2 hours, then being cooled, and the powder treated after hydrogen decrepitation process being taken out.

(120) Fine crushing process: performing jet milling to a sample in the crushing room under a pressure of 0.5 MPa and in the atmosphere of below 100 ppm of oxidizing gas, then obtaining an average particle size of 5.0 m of fine powder. The oxidizing gas means oxygen or water.

(121) Screening partial fine powder which is treated after the fine crushing process (occupies 30% of the total fine powder by weight), then mixing the screened fine powder and the unscreened fine powder. The powder which has a particle size smaller than 1.0 m is reduced to below 10% of total powder by volume in the mixed fine powder.

(122) Methyl caprylate is added into the powder treated after jet milling, the additive amount is 0.2% of the mixed powder by weight, further the mixture is comprehensively mixed by a V-type mixer.

(123) Compacting process under a magnetic field: a transversed type magnetic field molder being used, compacting the powder added with methyl caprylate in once to form a cube with sides of 25 mm in an orientation field of 1.8 T and under a compacting pressure of 0.2 ton/cm.sup.2, then demagnetizing the once-forming cube in a 0.2 T magnetic field.

(124) The once-forming compact is sealed so as not to expose to air, the compact is secondly compacted by a secondary compact machine (isostatic pressing compacting machine) under a pressure of 1.0 ton/cm.sup.2.

(125) Sintering process: moving each of the compact to the sintering furnace, firstly sintering in a vacuum of 10.sup.3 Pa and respectively maintained for 2 hours at 200 C. and for 2 hours at 800 C., then sintering for 2 hours at 1060 C., after that filling Ar gas into the sintering furnace so that the Ar pressure would reach 0.1 MPa, then being cooled to room temperature.

(126) Heat treatment process: annealing the sintered magnet for 1 hour at 420 C. in the atmosphere of high purity Ar gas, then being cooled to room temperature and taken out.

(127) Machining process: machining the sintered magnet after heat treatment as a magnet with 15 mm diameter and 5 mm thickness, the 5 mm direction being the orientation direction of the magnetic field.

(128) Directly testing the sintered magnet manufactured according to the embodiments 17, and the magnetic property is evaluated. The evaluation results of the magnets of the embodiments are shown in TABLE 15.

(129) TABLE-US-00016 TABLE 15 Evaluation of the microstructure of the embodiments Average amount of W in the Ratio of W- grain boundary rich phase amor- iso- number phase in the magnet WB.sub.2 phous tropic of No. (at %) (vol %) phase phase phase AGG 1 0.091 10.1 no no no 2 2 0.090 10.1 no no no 1 3 0.090 10.0 no no no 0 4 0.090 10.0 no no no 0 5 0.093 10.0 no no no 0 6 0.091 10.0 no no no 1 7 0.095 10.0 yes yes yes 2

(130) The amorphous phase and isotropic phase of TABLE 15 investigate the amorphous phase and isotropic phase of the alloy.

(131) The W-rich phase of TABLE 15 is a region above 0.004 at % and below 0.26 at %.

(132) TABLE-US-00017 TABLE 16 Magnetic property evaluation of the embodiments Br Hcj SQ (BH) max No. (kGs) (kOe) (%) (MGOe) BHH 1 14.02 14.2 98.2 45.67 59.87 2 13.91 14.7 98.1 45.17 59.87 3 13.79 15.4 99.67 44.37 59.77 4 13.67 17.4 99.78 43.63 61.03 5 13.6 17.9 99.85 43.15 61.05 6 13.41 19.2 98.25 41.89 61.09 7 13.2 20.4 82.45 40.7 61.1

(133) Through the manufacturing process, special attention is paid to the control of the contents of O, C and N, and the contents of the three elements O, C, and N are respectively controlled to 0.10.5 at %, below 0.3 at % and below 0.1 at %.

(134) Detecting the embodiments 17 with FE-EPMA (Field emission-electron probe micro-analyzer) [Japanese electronic kabushiki gaisya (JEOL), 8530F], which may be observed that, W is distributed with a high dispersity and performs a uniform pinning effect to the migration of the grain boundary, and the formation of AGG is prevented.

(135) Conclusion: by the analysis of FE-EPMA, when the content of Al is 0.82.0 at %, R.sub.6T.sub.13X (X=Al, Cu etc.) type phase comprising W is generated, the generation of this phase optimizes the coercivity and squareness and possess a weak magnetism, W is beneficial to the generation of R.sub.6T.sub.13X type phase and improves the stability.

Embodiment VI

(136) Respectively machining each group of sintered magnet manufactured in accordance with Embodiment I to a magnet with 15 mm diameter and 5 mm thickness, the 5 mm direction being the orientation direction of the magnetic field.

(137) Grain boundary diffusion treatment process: cleaning the magnet machined by each of the sintered body, adopting a raw material prepared by Dy oxide and Tb fluoride in a ratio of 3:1, fully spraying and coating the raw material on the magnet, drying the coated magnet, performing heat diffusion treatment in Ar atmosphere at 850 C. for 24 hours.

(138) Magnetic property evaluation process: testing the sintered magnet with Dy diffusion treatment by NIM-10000H type nondestructive testing system for BH large rare earth permanent magnet from China Jiliang University. The results are shown in TABLE 17:

(139) TABLE-US-00018 TABLE 17 Coercivity evaluation of the embodiments Hcj No. (kOe) 1 17.20 2 25.22 3 26.63 4 26.52 5 26.32 6 26.20 7 19.02

(140) It may be seen from TABLE 17, a minor amount of W of the present invention may generate a very minor amount of W crystal in the crystal grain boundary, and may not hinder the diffusion of RH, therefore the speed of diffusion is very fast. Furthermore, Nd-rich phase with a low melting point is formed as the comprising of appropriate amount of Cu, which may further performs the effect of promoting diffusion. Therefore, the magnet of the present invention is capable of obtaining an extremely high property and an enormous leap by the RH grain boundary diffusion.

Embodiment VII

(141) Raw material preparing process: preparing Nd, Dy and Tb respectively with 99.9% purity, B with 99.9% purity, Fe with 99.9% purity, and Cu, Co, Nb, Al and Ga respectively with 99.5% purity; being counted in atomic percent at %.

(142) In order to precisely control the using proportioning of W, the content of W of the Dy, Tb, Fe, B, Cu, Co, Nb, Al and Ga used in the embodiment is under the limit of the existing devices, the selected Nd further comprises W, the content of W element is 0.01 at %.

(143) The contents of each element are shown in TABLE 18:

(144) TABLE-US-00019 TABLE 18 Proportioning of each element (at %) No. Nd Dy Tb B Cu Co Nb Al Ga Fe 1 13.7 0.6 0.2 6.0 0.2 1.7 0.1 1.0 0.02 remainder 2 13.7 0.6 0.2 6.0 0.2 1.7 0.1 1.0 0.05 remainder 3 13.7 0.6 0.2 6.0 0.2 1.7 0.1 1.0 0.12 remainder 4 13.7 0.6 0.2 6.0 0.2 1.7 0.1 1.0 0.25 remainder 5 13.7 0.6 0.2 6.0 0.2 1.7 0.1 1.0 0.3 remainder 6 13.7 0.6 0.2 6.0 0.2 1.7 0.1 1.0 0.5 remainder 7 13.7 0.6 0.2 6.0 0.2 1.7 0.1 1.0 0.8 remainder 8 13.7 0.6 0.2 6.0 0.2 1.7 0.1 1.0 1.0 remainder

(145) Preparing 100 Kg raw material of each sequence number group by respective weighing in accordance with TABLE 18.

(146) Melting process: placing the prepared raw material into an aluminum oxide made crucible at a time, performing a vacuum melting in an intermediate frequency vacuum induction melting furnace in 10.sup.2 Pa vacuum and below 1500 C.

(147) Casting process: after the process of vacuum melting, filling Ar gas into the melting furnace so that the Ar pressure would reach 35000 Pa, then obtaining a quenching alloy by being casted by single roller quenching method at a quenching speed of 10.sup.2 C./s10.sup.4 C./s, thermal preservation treating the quenching alloy at 550 C. for 10 minutes, and then being cooled to room temperature.

(148) Hydrogen decrepitation process: at room temperature, vacuum pumping the hydrogen decrepitation furnace placed with the alloy, then filling hydrogen with 99.5% purity into the furnace until the pressure reach 0.085 MPa, after the alloy being placed for 160 minutes, vacuum pumping and heating at the same time, performing the vacuum pumping at 520 C. then being cooled, and the powder treated after hydrogen decrepitation process being taken out.

(149) Fine crushing process: performing jet milling to a sample in the crushing room under a pressure of 0.42 MPa and in the atmosphere with oxidizing gas below 10 ppm, then obtaining an average particle size of 4.28 m of fine powder. The oxidizing gas means oxygen or water.

(150) Methyl caprylate is added into the powder treated after jet milling, the additive amount is 0.25% of the mixed powder by weight, further the mixture is comprehensively mixed by a V-type mixer.

(151) Compacting process under a magnetic field: a transversed type magnetic field molder being used, compacting the powder added with methyl caprylate in once to form a cube with sides of 25 mm in an orientation field of 1.8 T and under a compacting pressure of 0.3 ton/cm.sup.2, then demagnetizing the once-forming cube in a 0.2 T magnetic field.

(152) The once-forming compact is sealed so as not to expose to air, the compact is secondly compacted by a secondary compact machine (isostatic pressing compacting machine) under a pressure of 1.0 ton/cm.sup.2.

(153) Sintering process: moving each of the compact to the sintering furnace, firstly sintering in a vacuum of 10.sup.3 Pa and respectively maintained for 3 hours at 300 C. and for 3 hours at 800 C., then sintering for 2 hours at 1030 C., after that filling Ar gas into the sintering furnace so that the Ar pressure would reach 0.1 MPa, then being cooled to room temperature.

(154) Heat treatment process: annealing the sintered magnet for 1 hour at 600 C. in the atmosphere of high purity Ar gas, then being cooled to room temperature and taken out.

(155) Machining process: machining the sintered magnet after heat treatment as a magnet with 10 mm diameter and 5 mm thickness, the 5 mm direction being the orientation direction of the magnetic field.

(156) Directly testing the sintered magnet manufactured according to the embodiments 18, and the magnetic property is evaluated. The evaluation results of the magnets of the embodiments are shown in TABLE 19 and TABLE 20.

(157) TABLE-US-00020 TABLE 19 Evaluation of the microstructure of the embodiments Average amount Ratio of W- of W in the rich phase amor- iso- number grain boundary in the magnet WB.sub.2 phous tropic of No. (at %) (vol %) phase phase phase AGG 1 0.088 10.0 no no no 8 2 0.089 10.1 no no no 1 3 0.090 10.0 no no no 0 4 0.093 10.01 no no no 0 5 0.092 9.98 no no no 0 6 0.090 9.99 no no no 1 7 0.090 10.1 no no no 1 8 0.089 10.0 no yes yes 1

(158) The amorphous phase and isotropic phase of TABLE 19 investigate the amorphous phase and isotropic phase of the alloy.

(159) The W-rich phase of TABLE 19 is a region with W content above 0.004 at % and below 0.26 at %.

(160) TABLE-US-00021 TABLE 20 Magnetic property evaluation of the embodiments Br Hcj SQ (BH) max No. (kGs) (kOe) (%) (MGOe) BHH 1 12.95 17.54 91.24 41.08 58.62 2 13.01 18.48 98.00 41.47 59.95 3 13.30 20.20 99.10 43.34 63.54 4 13.25 21.05 99.07 43.01 64.06 5 13.28 20.15 98.87 43.21 63.16 6 13.20 19.80 99.01 42.69 62.49 7 13.10 19.80 99.21 42.04 61.84 8 12.85 19.00 95.13 40.46 59.46

(161) Through the manufacturing process, special attention is paid to the control of the contents of O, C and N, and the contents of the three elements O, C, and N are respectively controlled to 0.10.5 at %, below 0.4 at % and below 0.2 at %.

(162) We may draw a conclusion that, when the content of Ga is below 0.05 at %, the dependency of heat treatment temperature of the coercivity may be increased, and the magnetic property is reduced, oppositely, when the content of Ga exceeds 0.8 at %, which induce the decrease of Br and (BH)max as Ga is a non-magnetic element.

(163) Similarly, detecting embodiment 18 with FE-EPMA [Japanese electronic kabushiki gaisya (JEOL), 8530F], which also may be observed that, W performs a uniform pinning effect to the migration of the grain boundary with a high dispersity, and the formation of AGG is prevented.

Embodiment VIII

(164) Raw material preparing process: preparing Nd, Dy, Gd and Tb respectively with 99.9% purity, B with 99.9% purity, and Cu, Co, Nb, Al and Ga respectively with 99.5% purity; being counted in atomic percent at %.

(165) In order to precisely control the using proportioning of W, the content of W of the Dy, Gd, Tb, Fe, B, Cu, Co, Nb, Al and Ga used in the embodiment is under the detecting limit of the existing devices, the selected Nd further comprises W, the content of W element is 0.01 at %.

(166) The contents of each element are shown in TABLE 21:

(167) TABLE-US-00022 TABLE 21 Proportioning of each element (at %) No. Nd Dy Gd Tb B Cu Co Nb Al Ga Fe 1 12.1 1 0.4 0.8 6.0 0.2 1.1 0.07 1.2 0.1 remainder 2 12.1 1 0.4 0.8 6.0 0.2 1.1 0.11 1.2 0.1 remainder 3 12.1 1 0.4 0.8 6.0 0.2 1.1 0.14 1.2 0.1 remainder 4 12.1 1 0.4 0.8 6.0 0.2 1.1 0.20 1.2 0.1 remainder 5 12.1 1 0.4 0.8 6.0 0.2 1.1 0.25 1.2 0.1 remainder

(168) Preparing 100 Kg raw material of each sequence number group by respective weighing in accordance with TABLE 21.

(169) Melting process: placing the prepared raw material into an aluminum oxide made crucible at a time, performing a vacuum melting in an intermediate frequency vacuum induction melting furnace in 10.sup.2 Pa vacuum and below 1450 C.

(170) Casting process: after the process of vacuum melting, filling Ar gas into the melting furnace so that the Ar pressure would reach 45000 Pa, then obtaining a quenching alloy by being casted by single roller quenching method at a quenching speed of 10.sup.2 C./s10.sup.4 C./s, thermal preservation treating the quenching alloy at 800 C. for 5 minutes, and then being cooled to room temperature.

(171) Hydrogen decrepitation process: at room temperature, vacuum pumping the hydrogen decrepitation furnace placed with the alloy, then filling hydrogen with 99.5% purity into the furnace until the pressure reach 0.09 MPa, after the alloy being placed for 150 minutes, vacuum pumping and heating at the same time, performing the vacuum pumping at 600 C. then being cooled, and the powder treated after hydrogen decrepitation process being taken out.

(172) Fine crushing process: performing jet milling to a sample in the crushing room under a pressure of 0.5 MPa and in the atmosphere with oxidizing gas below 30 ppm of, then obtaining an average particle size of 4.1 m of fine powder. The oxidizing gas means oxygen or water.

(173) Methyl caprylate is added into the powder treated after jet milling, the additive amount is 0.05% of the mixed powder by weight, further the mixture is comprehensively mixed by a V-type mixer.

(174) Compacting process under a magnetic field: a transversed type magnetic field molder being used, compacting the powder added with aluminum stearate in once to form a cube with sides of 25 mm in an orientation field of 1.8 T and under a compacting pressure of 0.3 ton/cm.sup.2, then demagnetizing the once-forming cube in a 0.2 T magnetic field.

(175) The once-forming compact is sealed so as not to expose to air, the compact is secondly compacted by a secondary compact machine (isostatic pressing compacting machine) under a pressure of 1.0 ton/cm.sup.2.

(176) Sintering process: moving each of the compact to the sintering furnace, firstly sintering in a vacuum of 10.sup.3 Pa and respectively maintained for 3 hours at 200 C. and for 3 hours at 800 C., then sintering for 2 hours at 1050 C., after that filling Ar gas into the sintering furnace so that the Ar pressure would reach 0.1 MPa, then being cooled to room temperature.

(177) Heat treatment process: annealing the sintered magnet for 2 hour at 480 C. in the atmosphere of high purity Ar gas, then being cooled to room temperature and taken out.

(178) Machining process: machining the sintered magnet after heat treatment as a magnet with 10 mm diameter and 5 mm thickness, the 5 mm direction being the orientation direction of the magnetic field.

(179) Directly testing the sintered magnet manufactured according to the embodiments 15, and the magnetic property is evaluated. The evaluation results of the magnets of the embodiments are shown in TABLE 22 and TABLE 23.

(180) TABLE-US-00023 TABLE 22 Evaluation of the microstructure of the embodiments Average amount Ratio of W- of W in the rich phase amor- iso- number grain boundary in the magnet WB.sub.2 phous tropic of No. (at %) (vol %) phase phase phase AGG 1 0.089 9.99 no no no 1 2 0.088 9.98 no no no 0 3 0.091 10.0 no no no 0 4 0.093 10.01 no no no 0 5 0.092 10.02 no yes yes 0

(181) The amorphous phase and isotropic phase of TABLE 23 investigate the amorphous phase and isotropic phase of the alloy.

(182) The W-rich phase of TABLE 23 is a region with W content above 0.004 at % and below 0.26 at %.

(183) TABLE-US-00024 TABLE 23 Magnetic property evaluation of the embodiments Br Hcj SQ (BH) max No. (kGs) (kOe) (%) (MGOe) BHH 1 12.30 22.8 95.16 37.2 60.0 2 12.28 22.9 95.57 36.8 59.7 3 12.24 23.9 99.30 36.4 60.3 4 12.22 23.8 99.01 36.4 60.2 5 11.75 18.4 85.25 33.7 52.0

(184) Through the manufacturing process, special attention is paid to the control of the contents of O, C and N, and the contents of the three elements O, C, and N are respectively controlled to 0.10.5 at %, below 0.4 at % and below 0.2 at %.

(185) We may draw a conclusion that, when the content of Nb is above 0.2 at %, the amorphous phases is observed in the quenching alloy sheet as the increasing of the content of Nb, and Br and Hcj are reduced as the existence of amorphous phase.

(186) Which is the same as the situation of adding Nb, by the experiments, the applicant found that the content of Zr should also be controlled below 0.2 at %.

(187) Similarly, detecting embodiment 15 with FE-EPMA [Japanese electronic kabushiki gaisya (JEOL), 8530F], as the detecting results, which may be observed that, W performs a uniform pinning effect to the migration of the grain boundary with a high dispersity, and the formation of AGG is prevented.

Embodiment IX

(188) Raw material preparing process: preparing Nd and Dy respectively with 99.5% purity, industrial FeB, industrial pure Fe, Co with 99.9% purity, Cu and Ga respectively with 99.9% purity, and W with 99.9% purity; being counted in atomic percent at %.

(189) In order to precisely control the using proportioning of W, the content of W of the Nd, Dy, Fe, B, Ga, Cu and Co used in the embodiment is under the detecting limit of the existing devices, the resource of W is from an extra added W metal.

(190) The contents of each element are shown in TABLE 24:

(191) TABLE-US-00025 TABLE 24 Proportioning of each element (at %) No. Nd Pr B W Ga Cu Co Fe 1 8.5 3.5 5.0 3*10.sup.4 0.5 0.2 2.5 remainder 2 8.5 3.5 5.0 5*10.sup.4 0.5 0.2 2.5 remainder 3 8.5 3.5 5.0 0.003 0.5 0.2 2.5 remainder 4 8.5 3.5 5.0 0.01 0.5 0.2 2.5 remainder 5 8.5 3.5 5.0 0.02 0.5 0.2 2.5 remainder 6 8.5 3.5 5.0 0.03 0.5 0.2 2.5 remainder 7 8.5 3.5 5.0 0.05 0.5 0.2 2.5 remainder

(192) Preparing 100 Kg raw material of each sequence number group by respective weighing in accordance with TABLE 24.

(193) Melting process: placing the prepared raw material into an aluminum oxide made crucible at a time, performing a vacuum melting in an intermediate frequency vacuum induction melting furnace in 10.sup.2 Pa vacuum and below 1500 C.

(194) Casting process: after the process of vacuum melting, filling Ar gas into the melting furnace so that the Ar pressure would reach 50000 Pa, then obtaining a quenching alloy by being casted by single roller quenching method at a quenching speed of 10.sup.2 C./s10.sup.4 C./s, thermal preservating the quenching alloy at 500 C. for 20 minutes, and then being cooled to room temperature.

(195) Detecting the quenching alloy sheets with FE-EPMA (Field emission-electron probe micro-analyzer) [Japanese electronic kabushiki gaisya (JEOL), 8530F], W is distributed in R-rich phase with a high dispersity. And, the W-rich region is distributed in the crystal grain boundary with a uniform dispersity, and occupies at least 50 vol % of the alloy crystal grain boundary, wherein, the W-rich region means a region with the content of W above 0.004 at % and below 0.26 at %.

(196) Hydrogen decrepitation process: at room temperature, vacuum pumping the hydrogen decrepitation furnace placed with the alloy, then filling hydrogen with 99.5% purity into the furnace until the pressure reaches 0.2 MPa, after the alloy being placed for 2 hours, vacuum pumping and heating at the same time, performing the vacuum pumping at 500 C., then being cooled, and the powder treated after hydrogen decrepitation process being taken out.

(197) Fine crushing process: performing jet milling to a sample in the crushing room under a pressure of 0.5 MPa and in the atmosphere of oxidizing gas below 50 ppm, then obtaining an average particle size of 3.50 m of fine powder. The oxidizing gas means oxygen or water.

(198) Methyl caprylate is added into the powder treated after jet milling, the additive amount is 0.3% of the mixed powder by weight, further the mixture is comprehensively mixed by a V-type mixer.

(199) Compacting process under a magnetic field: a transversed type magnetic field molder being used, compacting the powder added with methyl caprylate in once to form a cube with sides of 25 mm in an orientation field of 2.4 T and under a compacting pressure of 0.2 ton/cm.sup.2, then demagnetizing the once-forming cube in a 0.15 T magnetic field.

(200) The once-forming compact is sealed so as not to expose to air, the compact is secondly compacted by a secondary compact machine (isostatic pressing compacting machine) under a pressure of 1.2 ton/cm.sup.2.

(201) Sintering process: moving each of the compact to the sintering furnace, firstly sintering in a vacuum of 10.sup.3 Pa and respectively maintained for 3 hours at 200 C. and for 3 hours at 800 C., then sintering for 2 hours at 1000 C., after that filling Ar gas into the sintering furnace so that the Ar pressure would reach 0.1 MPa, then being cooled to room temperature.

(202) Heat treatment process: in the atmosphere of high purity Ar gas, performing a first order annealing for the sintered magnet for 1 hour at 850 C., then performing a second order annealing for 1 hour at 450 C., being cooled to room temperature and taken out.

(203) Machining process: machining the sintered magnet after heat treatment as a magnet with 15 mm diameter and 5 mm thickness, the 5 mm direction being the orientation direction of the magnetic field.

(204) Directly testing the sintered magnet manufactured according to the embodiments 17, and the magnetic property is evaluated. The evaluation results of the magnets of the embodiments are shown in TABLE 25 and TABLE 26.

(205) TABLE-US-00026 TABLE 25 Evaluation of the microstructure of the embodiments Average amount Ratio of W- of W in the rich phase amor- iso- number grain boundary in the magnet WB.sub.2 phous tropic of No. (at %) (vol %) phase phase phase AGG 1 0.002 1.8 no no no 20 2 0.004 2.0 no no no 1 3 0.020 3.5 no no no 0 4 0.090 5.0 no no no 0 5 0.168 7.8 no no no 0 6 0.250 9.8 no no no 0 7 0.440 11.0 yes yes yes 0

(206) The amorphous phase and isotropic phase of TABLE 25 investigate the amorphous phase and isotropic phase of the alloy.

(207) The W-rich phase of TABLE 25 is a region with W content above 0.004 at % and below 0.26 at %.

(208) TABLE-US-00027 TABLE 26 Magnetic property evaluation of the embodiments Br Hcj SQ (BH) max No. (kGs) (kOe) (%) (MGOe) BHH 1 12.54 8.2 76.4 35.2 43.7 2 14.9 15.6 98.5 53.3 68.8 3 14.8 15.9 99.5 52.57 68.5 4 14.78 15.8 99.3 52.4 68.2 5 14.72 15.7 98.2 52.0 67.7 6 14.62 15.4 98.8 51.3 66.7 7 13.16 13.28 88.5 38.2 51.4

(209) Through the manufacturing process, special attention is paid to the control of the contents of O, C and N, and the contents of the three elements O, C, and N are respectively controlled to 0.10.5 at %, below 0.1 at % and below 0.1 at %.

(210) We may draw a conclusion that, compared with the Embodiment I, when the content of rare earth element and B decreases, the ratio of the W-rich layer in the magnet also decreases. When the ratio of the W-rich layer in the magnet is less than 2%, the performance of the magnet drops sharply. And, when the content of W in the magnet is below 0.0005 at %, the pinning effect is hardly effective as the content of W is too low, and the existing of Cu in the raw material may easily causes AGG, and reduces SQ and Hcj, oppositely, when the content of W exceeds 0.03 at %, a part of WB.sub.2 phase may be generated, which reduces the squareness and magnetic property, furthermore, the amorphous phase and the isotropic phase may be generated in the obtained quenching alloy and which sharply reduces the magnetic property.

(211) Similarly, detecting embodiment 17 with FE-EPMA [Japanese electronic kabushiki gaisya (JEOL), 8530F], as the detecting results, which may be observed that, W performs a uniform pinning effect to the migration of the grain boundary with a high dispersity, and the formation of AGG is prevented.

(212) While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention.