US4837114A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing magnets having improved corrosion resistance
Assignee: Proterial Ltd
•
Filing: 1986-01-13
•
Granted: 1989-06-06
•
Expires: 2006-01-13
Abstract
Abstract Fe-B-R type permanent magnet is produced by: forming an anticorrosive coating film layer on a Fe-B-R base permanent magnet material body by means of vapor deposition to thereby improve the corrosion resistance thereof. The anticorrosive thin film is formed of metal, oxides, nitrides, carbides, borides, silicides, composite compositions thereof, or a mixture thereof. Additionally blasting, shot peening, heat treatment for forming an interdiffusion layer, and/or resin impregnation may be applied.
Inventors
- 👤 Takaki Hamada
- 👤 Tetsuji Hayakawa
- 👤 Yutaka Matsuura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:23
CPC Classifications
H; H01; H01F; H01F41/00; H01F41/02; H01F41/0253; H01F41/026; H01F1/00; H01F1/01; H01F1/03; H01F1/032; H01F1/04; H01F1/047; H01F1/053; H01F1/055; H01F1/057; H01F1/0571; H01F1/0572; H01F1/0575; H01F1/0577
Claims Analysis
Total Claims: 49
Claim 1
Independent Claim
160 words
A process for producing a permanent magnet, comprising: providing a sintered permanent magnet body consisting essentially of 10-30 at % R, wherein R is at least one element selected from the group consisting of Nd, Pr, Dy, Ho and Tb or a mixture of said at least one element and at least one other element selected from the group consisting of La, Ce, Sm, Gd, Er, Eu, Tm, Yb, Lu, Pm and Y, 2-28 at % B and at least 42 at % Fe, and wherein at least 50 vol % of the entire magnet material body consists of a Fe-B-R type tetragonal crystal structure; preparing the surface of the permanent magnet material body by blasting; and then forming a low gas permeability anticorrosive coating film layer on the permanent magnet material body by means of vapor deposition so that corrosive substances do not remain in the resultant permanent magnet, thereby improving the corrosion resistance of the resultant permanent magnet.
Claim 2
Dependent Claim
160 words
A process for producing a permanent magnet, comprising: providing a sintered permanent magnet body consisting essentially of 10-30 at % R, wherein R is at least one element selected from the group consisting of Nd, Pr, Dy, Ho and Tb or a mixture of said at least one element and at least one other element selected from the group consisting of La, Ce, Sm, Gd, Er, Eu, Tm, Yb, Lu, Pm and Y, 2-28 at % B and at least 42 at % Fe, and wherein at least 50 vol % of the entire magnet material body consists of a Fe-B-R type tetragonal crystal structure; preparing the surface of the permanent magnet material body by blasting; and then forming a low gas permeability anticorrosive coating film layer on the permanent magnet material body by means of vapor deposition so that corrosive substances do not remain in the resultant permanent magnet, thereby improving the corrosion resistance of the resultant permanent magnet.
Claim 3
Dependent Claim
148 words
A process for producing a permanent magnet, comprising: providing a sintered permanent magnet body consisting essentially of 10-30 at % R, wherein R is at least one element selected from the group consisting of Nd, Pr, Dy, Ho and Tb or a mixture of said at least one element and at least one other element selected from the group consisting of La, Ce, Sm, Gd, Er, Eu, Tm, Yb, Lu, Pm and Y, 2-28 at % B and at least 42 at % Fe, and wherein at least 50 vol % of the entire magnet material body consists of a Fe-B-R type tetragonal crystal structure; and forming a low gas permeability anticorrosive coating film layer on the permanent magnet material body by means of vapor deposition so that corrosive substances do not remain in the resultant permanent magnet, thereby improving the corrosion resistance of the resultant permanent magnet.
Claim 4
Dependent Claim
148 words
A process for producing a permanent magnet, comprising: providing a sintered permanent magnet body consisting essentially of 10-30 at % R, wherein R is at least one element selected from the group consisting of Nd, Pr, Dy, Ho and Tb or a mixture of said at least one element and at least one other element selected from the group consisting of La, Ce, Sm, Gd, Er, Eu, Tm, Yb, Lu, Pm and Y, 2-28 at % B and at least 42 at % Fe, and wherein at least 50 vol % of the entire magnet material body consists of a Fe-B-R type tetragonal crystal structure; and forming a low gas permeability anticorrosive coating film layer on the permanent magnet material body by means of vapor deposition so that corrosive substances do not remain in the resultant permanent magnet, thereby improving the corrosion resistance of the resultant permanent magnet.
Claim 5
Dependent Claim
33 words
A process as defined in claim 2, in which said anticorrosive thin film is formed of at least one selected from the group consisting of metals, oxides, nitrides, and carbides, and mixtures thereof.
Claim 6
Dependent Claim
49 words
A process as defined in claim 3, in which said anticorrosive thin film is formed of at least one selected from the group consisting of Al, Ni, Cr, Cu, Co, and alloys thereof, oxides of Si and Al, nitrides of Ti and Al, carbides of Ti, and mixtures thereof.
Claim 7
Dependent Claim
26 words
A process as defined in claim 2, in which said vapor deposition is effected by means of vacuum deposition, physical vapor deposition or chemical vapor deposition.
Claim 8
Dependent Claim
19 words
A process as defined in claim 5, in which said vapor deposition is effected by means of vacuum deposition.
Claim 9
Dependent Claim
18 words
A process as defined in claim 5, in which the vapor deposition is effected by physical vapor deposition.
Claim 10
Dependent Claim
20 words
A process as defined in claim 7, in which said physical vapor deposition is effected by means of ion plating.
Claim 11
Dependent Claim
20 words
A process as defined in claim 7, in which said physical vapor deposition is effected by means of ion sputtering.
Claim 12
Dependent Claim
32 words
A process as defined in claim 1, in which said blasting comprises blasting with hard particles having a mean particle size of 20-350 micrometers and a Mohs hardness of at least 5.
Claim 13
Dependent Claim
28 words
A process as defined in claim 10, in which said blasting is effected by blasting with said particles together with a pressurized gas of 1.0-6.0 kgf/cm 2 .
Claim 14
Dependent Claim
32 words
A process as defined in claim 2 or 1, in which shot peening is applied after said anticorrosive thin film has been formed on the surface of said permanent magnet material body.
Claim 15
Dependent Claim
33 words
A process as defined in claim 12, in which said shot peening involves blasting with spherical particles having a mean particle size of 30-3000 micrometers and a Mohs hardness of at least 3.
Claim 16
Dependent Claim
29 words
A process as defined in claim 13, in which said shot peening is effected by blasting with said particles together with a pressurized gas of 1.0-5.0 kgf/cm 2 .
Claim 17
Dependent Claim
23 words
A process as defined in claim 12, in which said shot-peened surface of said permanent magnet material body is further treated with chromating.
Claim 18
Dependent Claim
34 words
A process as defined in claim 2, 3 or 1, in which an interdiffusion layer is provided between the magnet material body and the anticorrosive coating film layer by heat treating the resultant mass.
Claim 19
Dependent Claim
22 words
A process as defined in claim 2, 3 or 1, which further comprises impregnating the anticorrosive coating film layer with a resin.
Claim 20
Dependent Claim
19 words
A process as defined in claim 16, which further comprises impregnating the anticorrosive coating film layer with a resin.
Claim 21
Dependent Claim
16 words
A process as defined in claim 17, in which said resin is a heat resistant resin.
Claim 22
Dependent Claim
16 words
A process as defined in claim 18, in which said resin is a heat resistant resin.
Claim 23
Dependent Claim
35 words
A process as defined in claim 16, in which the anticorrosive coating film layer is formed of a metal having a melting point not higher than the sintering temperature of the permanent magnet material body.
Claim 24
Dependent Claim
30 words
A process as defined in claim 1, in which the anticorrosive coating film layer is formed of metal and the surface of said coating film layer is subjected to passivation.
Claim 25
Dependent Claim
19 words
A process as defined in claim 2, wherein 50 at % or more of R is Nd and/or Pr.
Claim 26
Dependent Claim
42 words
A process as defined in claim 23, in which said permanent magnet material body comprises 12-24 at % R wherein at least 50 at % of R is Nd and/or Pr, 4-24 at % B and at least 52 at % Fe.
Claim 27
Dependent Claim
21 words
A process as defined in claim 24, in which Fe is present in an amount of at least 65 at %.
Claim 28
Dependent Claim
35 words
A process as defined in claim 2, in which Co is substituted for Fe up to 45 at % of the magnet material body provided that the resultant Fe is at least 27 at %.
Claim 29
Dependent Claim
24 words
A process as defined in claim 26, in which Co is substituted for Fe up to 35 at % of the magnet material body.
Claim 30
Dependent Claim
24 words
A process as defined in claim 27, in which Co is substituted for Fe up to 25 at % of the magnet material body.
Claim 31
Dependent Claim
24 words
A process as defined in claim 28, in which Co is substituted for Fe up to 20 at % of the magnet material body.
Claim 32
Dependent Claim
138 words
A process as defined in claim 2, in which said permanent magnet material body further comprises at least one of the following additional elements not exceeding the values specified below: 9.5 at % Al, 9.5 at % V, 8.0 at % Mn, 12.5 at % Nb, 9.5 at % Mo, 2.5 at % Sb, 3.5 at % Sn, 8.0 at % Ni, 1.1 at % Zn, and 4.5 at % Ti, 8.5 at % Cr, 5.0 at % Bi, 10.5 at % Ta, 9.5 at % W, 7 at % Ge, 5.5 at % Zr, 9.0 at % Si, 5.5 at % Hf, provided that, when two or more of said additional elements are contained, the total amount thereof does not exceed the highest value of the atomic percent of the element of said additional elements actually added.
Claim 33
Dependent Claim
85 words
A process as defined in claim 30, in which said permanent magnet material body contains at least one of the following additional elements not exceeding the values specified below: 6.4 at % Al, 6.6 at % V, 3.5 at % Mn, 10.0 at % Nb, 6.2 at % Mo, 1.4 at % Sb, 1.8 at % Sn, 3.3 at % Ti, 5.6 at % Cr, 5.0 at % Bi, 8.4 at % Ta, 5.9 at % W, 4.5 at % Ge, 3.7 at % Zr,
Claim 34
Dependent Claim
49 words
5 at % Ni, 0.5 at % Zn, and 5.0 at % Si, 3.7 at % Hf, provided that, when two or more of said additional elements are contained, the total amount thereof does not exceed the highest value of the atomic percent of said additional elements actually added.
Claim 35
Dependent Claim
49 words
5 at % Ni, 0.5 at % Zn, and 5.0 at % Si, 3.7 at % Hf, provided that, when two or more of said additional elements are contained, the total amount thereof does not exceed the highest value of the atomic percent of said additional elements actually added.
Claim 36
Dependent Claim
29 words
A process as defined in claim 21, in which the heat treatment is effected at a temperature ranging from 250° C. to the melting point of the metal employed.
Claim 37
Dependent Claim
31 words
A process as defined in claim 21, in which the heat treatment is effected at a temperature ranging from 250° C. to the aging temperature of the permanent magnet material body.
Claim 38
Dependent Claim
31 words
A process as defined in claim 12, in which an interdiffusion layer is provided between the magnet material body and the anticorrosive coating film layer by heat treating the resultant mass.
Claim 39
Dependent Claim
31 words
A process as defined in claim 15, in which an interdiffusion layer is provided between the magnet material body and the anticorrosive coating film layer by heat treating the resultant mass.
Claim 40
Dependent Claim
19 words
A process as defined in claim 12, which further comprises impregnating the anticorrosive coating film layer with a resin.
Claim 41
Dependent Claim
19 words
A process as defined in claim 15, which further comprises impregnating the anticorrosive coating film layer with a resin.
Claim 42
Dependent Claim
19 words
A process as defined in claim 34, which further comprises impregnating the anticorrosive coating film layer with a resin.
Claim 43
Dependent Claim
19 words
A process as defined in claim 35, which further comprises impregnating the anticorrosive coating film layer with a resin.
Claim 44
Dependent Claim
16 words
A process as defined in claim 36, in which said resin is a heat resistant resin.
Claim 45
Dependent Claim
16 words
A process as defined in claim 37, in which said resin is a heat resistant resin.
Claim 46
Dependent Claim
16 words
A process as defined in claim 38, in which said resin is a heat resistant resin.
Claim 47
Dependent Claim
16 words
A process as defined in claim 39, in which said resin is a heat resistant resin.
Claim 48
Dependent Claim
35 words
A process as defined in claim 39, in which the anticorrosive coating film layer is formed of a metal having a melting point not higher than the sintering temperature of the permanent magnet material body.
Claim 49
Dependent Claim
35 words
A process as defined in claim 35, in which the anticorrosive coating film layer is formed of a metal having a melting point not higher than the sintering temperature of the permanent magnet material body.
References Cited (Backward Citations)
JPS49500A
Cited
US4253886A
Cited
EP0012534A1
Cited
JPS5766604A
Cited
JPS5681908A
Cited
US4418473A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-05 | 1992-12-05 | 1993-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-05 | 1996-12-05 | 1997-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-05 | 2000-12-05 | 2001-06-06 | $7700.00 | Window Closed / Lapsed |