Process for producing permanent magnets and products thereof

Claim 2

A process for producing permanent magnet materials, which comprises the steps of: providing a sintered body composed of, in atomic percentage, 8-30% R (provided that R is at least one of rare earth elements including Y), 2-28% B, and the balance being Fe and inevitable impurities, subjecting the sintered body to a primary heat treatment at a temperature of 750°-1000° C. and below sintering temperature at which the density of the body has been increased by sintering, then cooling the resultant body to a temperature of no higher than 680° C. at a cooling rate of 3°-2000° C./min, and further subjecting the thus cooled body to a secondary heat treatment of 480°-700° C.

Claim 3

A process for producing permanent magnet materials, which comprises the steps of: providing a sintered body composed of, in atomic percentage, 8-30% R (provided that R is at least one of rare earth elements including Y), 2-28% B, no more than 50% Co (except for 0% Co), and the balance being Fe and inevitable impurities, subjecting the sintered body to a primary heat treatment at a temperature of 750°-1000° C. and below sintering temperature at which the density of the body has been increased by sintering, then cooling the resultant body to a temperature of no higher than 680° C. at a cooling rate of 3°-2000° C./min, and further subjecting the thus cooled body to a secondary heat treatment at a temperature of 480°-700° C.

Claim 4

A process for producing permanent magnet materials, which comprises the steps of: providing a sintered body composed of, in atomic percentage, 8-30% R (provided that R is at least one of rare earth elements including Y), 2-28% B, no more than 50% Co (except for 0% Co), and the balance being Fe and inevitable impurities, subjecting the sintered body to a primary heat treatment at a temperature of 750°-1000° C. and below sintering temperature at which the density of the body has been increased by sintering, then cooling the resultant body to a temperature of no higher than 680° C. at a cooling rate of 3°-2000° C./min, and further subjecting the thus cooled body to a secondary heat treatment at a temperature of 480°-700° C.

Claim 5

A process for producing permanent magnet materials, which comprises the steps of: providing a sintered body and composed of, in atomic percentage, 8-30% R (provided that R is at least one of rare earth elements including 7), 2-28% B, no more than the given percentage of at least one of the additional elements M (except for 0% M, and wherein M is: no more than 9.5% V, no more than 12.5% Nb, no more than 10.5% Ta, no more than 9.5% Mo no more than 9.5% W, no more than 8.5% Cr, no more than 9.5% Al, no more than 4.5% Ti, no more than 5.5% Zr, no more than 5.5% Hf, no more than 8.0% Mn, no more than 8.0% Ni, no more than 7.0% Ge, no more than 3.5% Sn, no more than 5.0% Bi, no more than 2.5% Sb, no more than 5.0% Si, and no more than 2.0% Zn, provided that in the case where two or more of M are contained, the sum thereof is no more than the maximum given percentage among the additional elements M as contained), and the balance being Fe and inevitable impurities, subjecting the sintered body to a primary heat treatment at a temperature of 750°-1000° C. and below sintering temperature at which the density of the body has been increased by sintering, then cooling the resultant body to a temperature of no higher than 680° C. at a cooling rate of 3°-2000° C./min, and further subjecting the thus cooled body to a secondary heat treatment at a temperature of 480°-700° C.

Claim 6

A process for producing permanent magnet materials, which comprises the steps of: providing a sintered body and composed of, in atomic percentage, 8-30% R (provided that R is at least one of rare earth elements including 7), 2-28% B, no more than the given percentage of at least one of the additional elements M (except for 0% M, and wherein M is: no more than 9.5% V, no more than 12.5% Nb, no more than 10.5% Ta, no more than 9.5% Mo no more than 9.5% W, no more than 8.5% Cr, no more than 9.5% Al, no more than 4.5% Ti, no more than 5.5% Zr, no more than 5.5% Hf, no more than 8.0% Mn, no more than 8.0% Ni, no more than 7.0% Ge, no more than 3.5% Sn, no more than 5.0% Bi, no more than 2.5% Sb, no more than 5.0% Si, and no more than 2.0% Zn, provided that in the case where two or more of M are contained, the sum thereof is no more than the maximum given percentage among the additional elements M as contained), and the balance being Fe and inevitable impurities, subjecting the sintered body to a primary heat treatment at a temperature of 750°-1000° C. and below sintering temperature at which the density of the body has been increased by sintering, then cooling the resultant body to a temperature of no higher than 680° C. at a cooling rate of 3°-2000° C./min, and further subjecting the thus cooled body to a secondary heat treatment at a temperature of 480°-700° C.

Claim 7

A process for producing permanent magnet materials, which comprises the steps of: providing a sintered body composed of, in atomic percentage, 8-30% R (provided that R is at least one of rare earth elements including Y), 2-28% B, no more than 50% Co (except for 0% Co), no more than the given percentage of at least one of the additional elements M (except for 0% M, and wherein M is: no more than 9.5% V, no more than 12.5% Nb, no more than 10.5% Ta, no more than 9.5% Mo no more than 9.5% W, no more than 8.5% Cr, no more than 9.5% Al, no more than 4.5% Ti, no more than 5.5% Zr, no more than 5.5% Hf, no more than 8.0% Mn, no more than 8.0% Ni, no more than 7.0% Ge, no more than 3.5% Sn, no more than 5.0% Bi, no more than 2.5% Sb, no more than 5.0% Si, and no more than 2.0% Zn, provided that in the case where two or more of M are contained, the sum thereof is no more than the maximum given percentage among the additional elements M as contained), and the balance being Fe and inevitable impurities, subjecting the sintered body to a primary heat treatment at a temperature of 750°-1000° C. and below sintering temperature at which the density of the body has been increased by sintering, then cooling the resultant body to a temperature of no higher than 680° C. at a cooling rate of 3°-2000° C./min, and further subjecting the thus cooled body to a secondary heat treatment at a temperature of 480°-700° C.

Claim 8

A process for producing permanent magnet materials, which comprises the steps of: providing a sintered body composed of, in atomic percentage, 8-30% R (provided that R is at least one of rare earth elements including Y), 2-28% B, no more than 50% Co (except for 0% Co), no more than the given percentage of at least one of the additional elements M (except for 0% M, and wherein M is: no more than 9.5% V, no more than 12.5% Nb, no more than 10.5% Ta, no more than 9.5% Mo no more than 9.5% W, no more than 8.5% Cr, no more than 9.5% Al, no more than 4.5% Ti, no more than 5.5% Zr, no more than 5.5% Hf, no more than 8.0% Mn, no more than 8.0% Ni, no more than 7.0% Ge, no more than 3.5% Sn, no more than 5.0% Bi, no more than 2.5% Sb, no more than 5.0% Si, and no more than 2.0% Zn, provided that in the case where two or more of M are contained, the sum thereof is no more than the maximum given percentage among the additional elements M as contained), and the balance being Fe and inevitable impurities, subjecting the sintered body to a primary heat treatment at a temperature of 750°-1000° C. and below sintering temperature at which the density of the body has been increased by sintering, then cooling the resultant body to a temperature of no higher than 680° C. at a cooling rate of 3°-2000° C./min, and further subjecting the thus cooled body to a secondary heat treatment at a temperature of 480°-700° C.

Claim 9

A process as defined in any one of claims 1-4, wherein said sintered body is an as-sintered body and is cooled at a cooling rate of at least 20° C./min.

Claim 10

A process as defined in any one of claims 1-4, wherein the primary heat treatment is conducted immediately following the sintering, or by reheating starting from any temperature below 750° C. after cooling.

Claim 11

A process as defined in claim 5, wherein after sintering the as-sintered body is cooled at a cooling rate of at least 100° C./min.

Claim 12

A process as defined in any one of claims 1-4, wherein the secondary heat treatment is conducted by starting from a temperature no higher than 680° C.

Claim 13

A process as defined in claim 8, wherein the secondary heat treatment is conducted at any time after said cooling to a temperature of no higher than 680° C.

Claim 14

A process as defined in claim 9, wherein the secondary heat treatment is conducted immediately following said cooling to a temperature of no higher than 680° C.

Claim 15

A process as defined in any one of claims 1-4, wherein the primary heat treatment is conducted at a temperature between 770°-950° C.

Claim 16

A process defined in any one of claims 1-4, wherein the primary heat treatment is conducted at a temperature between 790°-920° C.

Claim 17

A process as defined in any one of claims 1-4, wherein said cooling after the primary heat treatment is conducted at a cooling rate of 10°-1500° C./min.

Claim 18

A process as defined in claim 13, wherein said cooling rate is 20°-1000° C./min.

Claim 19

A process as defined in any one of claims 1-4, wherein the secondary heat treatment is conducted at a temperature between 520°-670° C.

Claim 20

A process as defined in claim 15, wherein the secondary heat treatment is conducted at a temperature between 550°-650° C.

Claim 21

A process as defined in any one of claims 1-4, wherein the heat treatments are conducted in vacuum or in an atmosphere of inert or reducing gas.

Claim 22

A process as defined in claim 17, wherein the vacuum is at 10 -3 Torr or less.

Claim 23

A process as defined in claim 17, wherein the atmosphere gas has a purity of at least 99.99%.

Claim 24

A process as defined in any one of claims 1-4, wherein R includes at least one selected from a group consisting of Nd, Pr, Dy, Tb and Ho.

Claim 25

A process as defined in claim 20, wherein R includes at least one selected from a group consisting of Nd, Pr, Dy, Tb and Ho and at least one rare earth elements except for said group.

Claim 26

A process as defined in claim 20, wherein at least 50% of the entire R is the sum of Nd and/or Pr.

Claim 27

A process as defined in any one of claims 1-4, wherein R is 12-24% and B is 3-27%.

Claim 28

A process as defined in claim 23, wherein R is 12-20% and B is 5-24%.

Claim 29

A process as defined in claim 24, wherein R is 12.5-20% and B is 5-15%.

Claim 30

A process as defined in claim 25, wherein R is 13-18% and B is 5-15%.

Claim 31

A process as defined in claim 26, wherein B is 5-11%.

Claim 32

A process as defined in claim 27, wherein R is 13-16% and B is 6-11%.

Claim 33

A process as defined in claim 28, wherein R is 13-14.5% and B is 6-7%.

Claim 34

A process as defined in claim 25, wherein Fe, or the sum of Fe, Co and M is 65-82.5%.

Claim 35

A process as defined in claim 26, wherein Fe, or the sum of Fe, Co and M is 67-82%.

Claim 36

A process as defined in claim 26, wherein at least 80% of the entire R is the sum of Nd and/or Pr.

Claim 37

A process as defined in claim 32, wherein R is Nd and/or Pr.

Claim 38

A process as defined in claim 2 or 4, wherein Co is 0.1-35%.

Claim 39

A process as defined in claim 34, wherein Co is 5-25%.

Claim 40

A process as defined in claim 34, wherein Co is no more than 23%.

Claim 41

A process as defined in claim 28, wherein Co is no more than 15% and M is no more than 2%.

Claim 42

A process as defined in claim 29, wherein Co is no more than 10% and M is no more than 1%.

Claim 43

A process as defined in claim 3 or 4, wherein M is at least 0.1%.

Claim 44

A process as defined in claim 39, wherein M is no more than the following given percentage provided that the sum of M is no more than the maximum given percentage among the respective additional elements M contained where two or more M are contained: ______________________________________ 8.0% V, 10.5% Nb, 9.5% Ta, 7.5% Mo, 7.5% W, 6.5% Cr, 7.5% Al, 4.0% Ti, 4.5% Zr, 4.5% Hf, 6.0% Mn, 3.5% Ni, 5.5% Ge, 2.5% Sn, 4.0% Bi, 1.5% Sb, 4.5% Si, and 1.5% Zn. ______________________________________

Claim 45

A process as defined in claim 40, wherein M is no more than the following given percentage provided that the sum of M is no more than the maximum given percentage among the respective additional elements M contained where two or more M are contained: ______________________________________ 6.5% V, 8.5% Nb, 8.5% Ta, 5.5% Mo, 5.5% W, 4.5% Cr, 5.5% Al, 3.5% Ti, 3.5% Zr, 3.5% Hf, 4.0% Mn, 2.0% Ni, 4.0% Ge, 1.0% Sn, 3.0% Bi, 0.5% Sb, 4.0% Si, and 1.0% Zn. ______________________________________

Claim 46

A process as defined in claim 41, wherein M is at least one selected from the group consisting of V, Nb, Ta, Mo, W, Cr and Al and the sum of M is no more than 3%.

Claim 47

A process as defined in any one of claims 1-4, wherein the sintered body is magnetically anisotropic.

Claim 48

A process as defined in any one of claims 1-4, wherein the sintered body is magnetically isotropic and wherein R is 10-25% and B is 3-23%.

Claim 49

A process as defined in claim 44, wherein R is 12-20%, B is 5-18% and Co is no more than 35%.

Claim 50

A process as defined in claim 45, wherein R is 12-16%, B is 6-18% and Co is no more than 25%.

Claim 51

A process as defined in claim 3 or 4, provided that with respect to V, W, Ti, Ni and Ge, the given percentage is as follows: no more than 10.5% V, no more than 8.8% W, no more than 4.7% Ti, no more than 4.7% Ni, and no more than 6.0% Ge.

Claim 52

A process as defined in claim 43, wherein Fe or the sum of Fe, Co and M is 71-82%.

Claim 53

A process as defined in any one of claims 1-4, wherein the sintered body has been sintered at a temperature ranging from 900° to 1200° C.

Claim 54

A process as defined in claim 25, wherein R is 12.5-14.5% and B is 5-7%.