CN1027473C - Anticorrosive rare-earth-transition metal series magnet and method thereof - Google Patents
Anticorrosive rare-earth-transition metal series magnet and method thereof Download PDFInfo
- Publication number
- CN1027473C CN1027473C CN 90109219 CN90109219A CN1027473C CN 1027473 C CN1027473 C CN 1027473C CN 90109219 CN90109219 CN 90109219 CN 90109219 A CN90109219 A CN 90109219A CN 1027473 C CN1027473 C CN 1027473C
- Authority
- CN
- China
- Prior art keywords
- phase
- magnet
- mutually
- transition metal
- rare earth
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Hard Magnetic Materials (AREA)
Abstract
A two-phase permanent magnet which has not only excellent magnetic characteristics but also significantly high corrosion resistance. It is manufactured by use of two magnetically useful phases as the starting materials. One is an RE2TM14B phase having a high residual flux density; the other is a low-melting RE-TM phase and/or RE-TM-B phase which contributes to the improvement of sinterability and has a function of cleaning the main phase grain boundary and a property of causing the resultant material to be an electrochemically noble composition.
Description
The present invention relates to a kind of not only excellent in magnetic characteristics but also corrosion resistance and temperature characterisitic also good rare earth-transition metal based magnet and manufacture method thereof.
As the present representational permanent magnet material of producing, what can list has alnico Al-Ni-Co series magnet, ferrite lattice and a rare earth element magnet.The production history of alnico Al-Ni-Co series magnet is very long, but owing to develop cheap ferrite lattice and the rare earth element magnet with higher magnetic characteristic in succession, its demand is constantly descended.On the other hand, ferrite lattice is owing to be primary raw material with the oxide, thereby stable chemical performance and cost are low, still occupy an leading position in ferromagnetic material now, but that its shortcoming is a maximum magnetic energy product is less.
Occur the Sm-Co based magnet that magnetic moment that magnetic anisotropy that rare earth ion is had and transition metal have combines after this, improved maximum magnetic energy product in the past significantly.But because the Sm-Co based magnet is a main component with the Sm and the Co of natural resources shortage, this just causes its price high inevitably.
For this reason, people developing always do not contain high Sm of price and Co, low price and magnetic alloy with high magnetic characteristic.As a result, assistant people such as river adopts and waters the knot method and develop stable ternary alloy (special public clear 61-34242 and spy open clear 59-132104).In addition, people such as J.J.Croat adopts the melt supercooled method to develop the alloy of high-coercive force (special beginning 59-64739).These magnet are made up of Nd, Fe and B, and its maximum magnetic energy product surpasses the Sm-Co based magnet.
But in the composition of Nd-Fe-B based magnet, active very high light rare earth element such as Nd and the Fe content that easily gets rusty are higher, thereby corrosion resistance is poor, thereby cause magnetic characteristic to worsen, lack these shortcomings of reliability as industrial materials.
In order to improve corrosion resistance, people have taked various measures, for example sintered magnet is imposed electroplating surface (spy opens clear 63-77103), coating and handle (spy opens clear 60-63901) etc., and to resin bound type magnet, carry out measures such as surface preparation before with magnetic and mixed with resin.Long-term, the effective antirust processing but above-mentioned any method all can not be said so in addition, also has because of above-mentioned processing cost is improved and to cause problem such as flux loss owing to diaphragm.
As the measure that addresses the above problem, the inventor once proposed to replace the Fe in the Nd-Fe-B based magnet densely and obtain rare earth-transition metal-boron series magnetic alloy (spy opens flat 2-4939) with Co and Ni height in the past
The corrosion resistance of above-mentioned magnet is good, and the Curie point rising, so reliability of material improves significantly.
The invention relates to the rare earth-transition metal based magnet that above-mentioned magnet is further improved, becomes two phase constitutions.
Nd based magnet about two phase constitutions, the someone proposed to adopt two alloyages that rich rare earth is made the magnet (spy opens clear 63-93841 and the spy opens clear 63-164403) that has excellent magnetic characteristics with the mixing mutually of greedy rare earth, liquid-phase sintering mutually in the past, but, adopt said method, though magnetic characteristic has improved, but corrosion resistance still has problems.
The objective of the invention is, address the above problem, provide a kind of not only magnetic characteristic good, and have the rare earth-transition metal based magnet of two phase constitutions of fabulous corrosion resistance and favourable manufacture method thereof.
Solution process of the present invention at first is described.
The inventor scrutinizes the metal microstructure of above-mentioned magnet with high-resolution electron microscope etc., and knot as find out exists the Nd with big saturation flux density in this magnet
2(Fe, Co, Ni)
14B demonstrates strong coercitive crystal boundary phase Nd mutually and round the crystal grain that is formed mutually by this
2(Fe, Co, Ni)
17, Nd(Fe, Co, Ni)
5, Nd
2(Fe, Co, Ni)
7, Nd(Fe, Co, Ni)
4B and Nd(Fe, Co, Ni)
12B
6, and the Nd that forms the CrB structure
1-XTM
1(but TM mainly is Ni) etc.
Find out also that simultaneously the amount of Nd phase that becomes the corrosion origination point is few more, and Ni and the concentration of Co of above-mentioned crystal boundary in mutually is high more, then corrosion resistance is just good more.
The inventor further studies repeatedly for this point, found that, removes Nd
2(Fe, Co, Ni)
17In addition, above-mentioned crystal boundary is difficult to occur in Nd-Fe-B is the scope of ternary phase diagrams, and they can only appear in the scope of Nd-Co-B system.
For ease of reference, figure 1 illustrates Nd-Fe-B ternary phase diagrams (N.F.Chaban, yu.B.Kuzma, N.S.Bilonizhko, O.O.Kachmar and N.U.Petrov, Akad, Nauk, SSSR, SetA, Fiz.-Mat.Tekh, Nauki No.10(1979) 873), Nd-Co-B ternary phase diagrams shown in Figure 2 (N.S.Bilonizhko and Yu.B.Kuzma, Izv.Akad.Nauk SSSR Neorg.Mater, 19(1983) 487).But former paper is with the Nd among the figure
2, Fe
14B is write as Nd mutually by mistake
2, Fe
9The B phase is with Nd
2Co
14B is write as Nd mutually by mistake
2Co
9Therefore the B phase has done correction in Fig. 1 and Fig. 2.
In Fig. 1, the numbering 1 be Nd mutually
2Fe
14The B phase, the composition around it has NdFe
4B
4Phase (phase of numbering 2), Nd phase, Nd
2Fe
17Mutually with Fe mutually.Yet in Fig. 2, by the Nd of numbering 1
2Co
14Show Nd in the magnet that the periphery composition of B phase is made
2Co
17Phase, NdCo
5Phase, Nd
2Co
7Phase, NdCo
4B phase (phase of numbering 2) and NdCo
12B
6Phases (phase of numbering 7) etc., original Nd should not occur under poised state.
As previously mentioned, Nd is not only the position that corrosion takes place mutually, and is the phase that magnetic is not had contribution, is the phase that should get rid of therefore.
Therefore, in the present invention with to contributive two phases of magnetic, the i.e. high RE of resideual flux density
2TM
14B mutually and improve agglutinating property, again have the principal phase crystal boundary effect of cleaning and serve as aspect the electrochemistry good composition low melting point RE-TM ' mutually or RE-TM '-B mutually for parent material manufacturing two-phase magnet, obtain all good permanent magnets of magnetic characteristic and corrosion resistance in this way.
Be that the present invention is a kind of corrosion resistant rare earth-transition metal based permanent magnet, it is characterized in that, this permanent magnet contains more than the RE:10 atom %, 25 atom % following (RE is one or two or more kinds that select from y, Sc and lanthanide series herein), more than the B:2 atom %, below the 20 atom %, remainder be basically TM(but TM is one or two or more kinds that select from Fe, Co and Ni), the tissue of magnet is by having Nd
2Fe
14The RE of B structure
2TM
14B(TM herein is same as described above) phase of this composition with than this mutually low-melting RE-TM ' be intermetallic chemicals phase (but TM ' be Ni or Ni be selected from Fe, Co in the mixture of at least a element) or RE-TM ' be eutectic structure (TM ' is same as described above herein) and/or RE-TM '-B series intermetallic compound mutually (TM ' is same as described above herein) form.
In addition, the present invention is a kind of manufacture method of corrosion resistant rare earth-transition metal based magnet, and this method comprises: will be with RE
2TM
14B series intermetallic compound phase (but TM is one or two or more kinds that select from Fe, Co and Ni) for the powder of main body and the RE-TM ' that is lower than this powder based on fusing point be the intermetallic chemicals mutually (but TM is Ni or Ni and the mixture that is selected from least a element among Fe, the Co) or RE-TM ' be the mixed-powder extrusion forming of the powder constituent of eutectic structure (TM ' is same as described above herein) and/or RE-TM '-B series intermetallic compound phase (TM ' is same as described above herein), carry out sintering then.
In the present invention, for further improving corrosion resistance, effectively way is to make crystal boundary be better than principal phase aspect chemical property, thereby preferably to improve Ni and/or Co be to be shared ratio among the TM ' of low melting point in mutually with RE-TM '-B at RE-TM ', makes to be higher than them at RE
2TM
14The ratio of B in mutually.The ratio that particularly improves Ni is for improving corrosion resistance and reducing cost especially effective.
In addition, in the present invention, by the RE of formula weight unit
2TM
14The B intermetallic compound with RE-TM ' is, RE-TM '-B series intermetallic compound ratio mutually be 95: 5 to 40: 60 more satisfactory.Why so be because, if the ratio of the two exceeds beyond the above-mentioned scope, will cause coercive force and saturation flux density significantly to worsen, this is very disadvantageous.Here so-called formula weight (formula unit) just is equivalent to for example Nd
2Fe
14B regards the situation of a molecule (being referred to as formula in solid) as.In order to handle easily and to mix, supply to mix each particles of powder diameter of usefulness preferably about 0.5-5 μ m.
Here, compare RE
2TM
14The mutually low-melting RE-TM ' of B intermetallic compound series intermetallic compound phase (also comprise eutectic structure, down with) and RE-TM '-B series intermetallic compound phase is representational composed as follows.
RE-TM ' is
RE
2TM
17', RETM
5', RE
2TM
7', RETM
3', RETM
2', RE
1TM '
1-X, RE
7TM
3', RE
3TM ' and RE-TM ' eutectic structure
RE-TM '-B system
RETM
4′B、RE
3TM
11′B
4、RE
2TM
5′B
2、RE
2TM
7′B
3、RE
2TE
5′B
3、RETM
12′B
6、RETM
2′B
2、RETM
9′B
4、RE
2TM′B
3
In addition, with above-mentioned RE
2TM
14B can make as follows with the powder that with RE-TM ' is, RE-TM '-B series intermetallic compound is principal phase mutually.
I.e. composition weighing in accordance with regulations respectively constitutes the element monomer, adopts electric arc melting and even high frequency to fuse in a vacuum or prepares alloy pig in the inert atmosphere.Then equally in a vacuum or in the inert atmosphere this alloy pig is kept the 1-30 angel under 600-1000 ℃ of temperature it becomes single-phase intermetallic compound.In general, because intermetallic compound has to a certain degree the solid solution scope of (～20%) mutually mostly, corresponding therewith, initial composition also allows certain compositing range.
Single-phase intermetallic compound after with the hammer-mill coarse crushing, is made the attritive powder of diameter 0.5-5 μ m again with jet pulverizer or vertical ball mill.In addition, in low melting point phase RE-TM ', RE-TM '-B, because of hardness is low, pulverizing is had any problem.If before hammer-mill is pulverized, be placed in advance in the temperature range of room temperature to 350 ℃ and keep a few hours to make it that hydrogen embrittlement take place, then just than being easier to pulverizing.
According to the present invention, with previously prepared, to have RE
2TM
14The intermetallic compound that B forms be main body powder with than its low-melting, previously prepared RE-TM ' series intermetallic compound or RE-TM '-B series intermetallic compound be that more than one of powder of principal phase mix, sintering after the compacting, combustion, thereby make it have both high magnetic characteristic and highly corrosion resistant.
Its reason can be thought because than RE
2TM
14When the B intermetallic compound is the low-melting powder acceleration of sintering of the powder of main body mutually at RE
2TM
14The intercrystalline of B forms the crystal boundary phase, has the cause that improves the coercive force effect.
In addition, at RE
2TM
14B mutually in, from the size of magnetic moment and with the viewpoint of the magnetic couplings of TM atom and consider cost, RE is Nd or Pr preferably, can certainly adopt other rare earth, besides the combination of they and Nd, Pr.
As for TM, one or two or more kinds that select from Fe, Co and Ni preferably particularly from the viewpoint of the high corrosion-resistant of magnet, wishes that the ratio of Ni is big.In addition, because RE
2TM
14B bears the saturation flux density of magnet mutually, therefore wish that the ratio that exists of Fe among the TM, Co and Ni is Fe: above, the discontented 73 atom % of 10 atom %, Co: more than the 7 atom %, below the 50 atom %, Ni: more than the 5 atom %, below the 30 atom %, as the Fe of TM, because with 100% RE
2TM
14B is under the situation of principal phase, and the corrosion resistance of permanent magnet of the present invention is also good than in the past RE-TM-B magnet, therefore, and according to the purposes of magnet, certainly as principal phase.
Secondly, as RE-TM ' is to be the RE of low melting point in mutually with RE-TM '-B, if emphasis cost, rare earth elements such as the most handy so La, Ce, Pr, Nd, if wish further to improve corrosion resistance, then adopt atomic number after Sm in to the Lu gently, heavy rare earth element or Y, Sc etc. are more suitable.
About TM ', contain Ni and/or Co, particularly to contain Ni very effective for improving corrosion resistance, therefore must contain Ni as TM ' in the present invention, its containing ratio in TM ' is comparatively suitable more than 8%.
The effect of adding Ni is as follows:
ⅰ) reduce the fusing point that RE-TM ' is and RE-TM '-B is, when liquid-phase sintering, promote liquid phase to soak into, improve sintered density, improve resideual flux density.
ⅱ) based on above-mentioned ⅰ) identical reason, the crystal boundary cleaning performance of the liquid phase when improving liquid-phase sintering has the coercitive effect of further raising.
ⅲ) the corrosion proof effect of improvement is stronger than Co, and price is also low than Co.
In addition, be higher than at RE by the ratio that makes middle mutually Ni of low melting point and/or Co
2TM
14The ratio of B in mutually can further improve corrosion resistance.This be because, if the formation of TM is identical, so in sintered body these powder tend to compare RE mutually
2TM
14B preferentially corrodes at the crystal boundary place.Therefore, improve chemical property in advance and will play advantageous effect.Because can get rid of the Nd phase of magnetic not being had contribution, thereby the resideual flux density increase, the result has also improved maximum magnetic energy product (BH) max.
As in the past, the initial overall average assay molten alloy of magnet of pressing, pulverize then, compacting, sintering, even also can produce the Nd phase near poised state, therefore long-time heating at high temperature, crystal grain takes place to grow up unusually in heating process, the shortcoming that causes coercive force significantly to descend.
The RE of principal phase not necessarily must be an identity element with low melting point RE mutually.Be in the magnet of principal component with being selected from the part that at least a element among Mg, Al, Si, Ti, V, Cr, Mn, Cu, Ag, Au, Cd, Rh, Pd, Ir, Pt, Zn, Ga, Ge, Zr, Nb, Mo, In, Sn, Hf, Ta and the W replaces RE and TM with above-mentioned two-phase, even replace 8 overall atom % of magnet, effect of the present invention can not lost yet.
About manufacture method, remove the above and will consist of RE
2TM
14The powder of B with based on low-melting RE-TM ' be and/or the mixed-powder extrusion forming of RE-TM '-B series intermetallic compound powder constituent mutually, then outside the method for sintering, manufacture method as large-scale magnet, also above-mentioned mixed-powder can be placed steel pipe, vacuum seal, then limit hot rolling limit sintering.But what can lose some magnetic characteristics in this way.
The simple declaration of accompanying drawing:
Fig. 1 is the Nd-Fe-B ternary phase diagrams, and Fig. 2 is the Nd-Co-B ternary phase diagrams.
Be optimum implementation of the present invention below.
By the atomic ratio of neodymium, transition metal and boron is to carry out electric arc melting at 2: 14: 1, makes the alloy fritter, and the homogenizing of carrying out under 950 ℃ in vacuum furnace 7 days is handled, and it is broken to carry out coarse crushing and micro mist then, obtains diameter and be several microns attritive powder.And in this process, the ratio of the Fe in the transition metal, Co, Ni is done various changes, make some kinds of alloy powders.
Similarly, preparation Nd or (Nd+Dy) be 1: 1 powder with the ratio of Ni.At this moment homogenizing treatment conditions are 680 ℃, 5 days.
Next, from above-mentioned two groups, respectively select a kind ofly, they mixed, suppress while apply the magnetic field of 15KOe in the various ratios shown in the table 1, then under vacuum atmosphere in 1000 ℃ of sintering 2 hours, be chilled to room temperature subsequently.
The magnetic characteristic and the etching characteristic of test gained sample the results are shown in the table 1.Sample is exposed in the environment of 70 ℃ of temperature, humidity 95% and reaches 48 hours, evaluate its etching characteristic by the long-pending corrosion area occupation ratio of specimen surface then.
In table 1, for the ease of relatively, will list in the lump according to the test result of the sample of previous methods manufacturing, described previous methods comprises initial just by operations such as compacting-sintering in the broken magnetic field of overall composition melting, coarse crushing one micro mist of sintered magnet.
Be clear that from table 1 the rare earth-transition metal based magnet of two phase constitutions of the present invention is just compared by the magnet of overall composition melting with the initial of prior art, magnetic characteristic still is that corrosion resistance has all improved significantly.
(table 1, table 1 continuous see literary composition back)
By the atomic ratio of neodymium, transition metal and boron is to carry out electric arc melting at 2: 14: 1, makes the alloy fritter, and the homogenizing of carrying out under 950 ℃ in vacuum furnace 7 days is handled, and coarse crushing and micro mist are broken then, obtain the attritive powder of several microns of diameters.And in this process, the ratio of the Fe in the transition metal, Co, Ni is done various changes, thereby make some kinds of alloy powders.
Preparing Nd and/or Dy or Pr and Ni or atomic ratio (Ni+Co) by the same manner is 3: 1 powder.At this moment, the condition of homogenizing processing is 485 ℃, 5 days.
The magnetic characteristic and the etching characteristic of test gained sample, gained the results are shown in the table 2.
For ease of reference, in table 2, list the performance investigation result of opening the magnet of the technology manufacturing shown in the clear 63-164403 by the spy in the lump
As shown in Table 2, the rare earth-transition metal based magnet of two phase constitutions of the present invention has good magnetic characteristic and corrosion resistance.Relatively being fit to example 8 and suitable example 13 can obviously find out, at RE
3(Ni, Co)
1The ratio of middle Ni is high more, and then corrosion resistance is good more.In addition, with regard to the past example, though its magnetic characteristic is good, owing to do not contain Ni thereby corrosion-resistant.
(table 2, table 2 continuous see literary composition back)
Embodiment 3
Prepare RE according to similarly to Example 1 mode
2TM
14The micro-alloy powder of B composition.As the powder stock that mixes with it, preparation Ni and Co shared ratio in TM ' are higher than RE
2TM
14The micro-alloy powder of B powder.After their are mixed, make sintered magnet according to mode similarly to Example 1.
The characteristic of gained sintered magnet is compared with the sintered magnet that obtains by previous methods, and be shown in Table 3.
Can obviously find out by table 3,, use to be higher than RE at middle Ni of TM ' and the shared ratio of Co as mixed-powder
2TM
14During the micro-alloy powder of B powder, corrosion resistance will further be improved.
Compare with manufacture method in the past, adopt the present invention can produce corrosion resistance and improve and the also improved rare earth-transition metal based magnet of magnetic characteristic, particularly because corrosion proof improvement has improved the reliability as industrial materials significantly.
(table 3, table 3 continue)
Claims (3)
1, corrosion resistant rare earth-transition metal based permanent magnet, it is characterized in that: this alni magnet contains more than the RE:10 atom %, 25 atom % following (RE is select from Rr, Nd, Dy at least a herein), more than the B:2 atom %, below the 20 atom %, remainder is made of TM (still, TM is select from Fe, Co and Ni at least a) in fact; The tissue of magnet is by having Nd
2Fe
14The RE of B structure
2TM
14The phase that B (TM herein is same as described above) forms, (still than this mutually low-melting RE-TM ' series intermetallic compound phase, TM ' is Ni, the mixture of Ni and Fe, the mixture of Ni and Co, or the mixture of Ni, Fe and Co) or RE-TM ' be that eutectic structure (TM ' herein is same as described above) constitutes, the surface corrosion rate after its humid test of 48 hours is below 5%.
2, corrosion resistant rare earth-transition metal based permanent magnet as claimed in claim 1 is characterized in that: making at RE-TM ' is that Ni and/or Co ratio shared among the TM of low melting point phase is higher than at RE
2TM
14B this ratio in mutually, and the ratio of Fe if with the More than expression, be below 0.3.
3, corrosion resistant rare earth-transition metal based permanent magnet as claimed in claim 1, it is characterized in that: RE-TM ' is that low melting point is by RE
3TM
1', RE with CrB structure
1TM
1' or the eutectic structure of these phases constitute.
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP263,946/89 | 1989-10-12 | ||
| JP26394689 | 1989-10-12 | ||
| JP335,028/89 | 1989-12-26 | ||
| JP2269635A JP2675430B2 (en) | 1989-10-12 | 1990-10-09 | Corrosion resistant rare earth-transition metal magnet and method of manufacturing the same |
| JP269,635/90 | 1990-10-09 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1051818A CN1051818A (en) | 1991-05-29 |
| CN1027473C true CN1027473C (en) | 1995-01-18 |
Family
ID=26546272
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 90109219 Expired - Fee Related CN1027473C (en) | 1989-10-12 | 1990-10-12 | Anticorrosive rare-earth-transition metal series magnet and method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1027473C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109313972A (en) * | 2016-05-30 | 2019-02-05 | 住友电气工业株式会社 | The method for manufacturing the method for coating Magnaglo, manufacturing the method for dust core and manufacturing electromagnetic component |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5742813B2 (en) * | 2012-01-26 | 2015-07-01 | トヨタ自動車株式会社 | Rare earth magnet manufacturing method |
| CN114005633B (en) * | 2021-10-21 | 2022-11-15 | 钢铁研究总院 | Rare earth soft magnetic material with multi-shell structure and preparation method thereof |
-
1990
- 1990-10-12 CN CN 90109219 patent/CN1027473C/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109313972A (en) * | 2016-05-30 | 2019-02-05 | 住友电气工业株式会社 | The method for manufacturing the method for coating Magnaglo, manufacturing the method for dust core and manufacturing electromagnetic component |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1051818A (en) | 1991-05-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101521068B (en) | Rare earth permanent magnet and method of manufacturing the same | |
| WO2012002059A1 (en) | R-t-b type rare earth permanent magnet, motor, automobile, power generator, and wind power generation system | |
| CN1246864C (en) | Method for preparation of permanent magnet | |
| CN1019245B (en) | Corrosion resisting rare-earth metal magnet | |
| JPWO2002103719A1 (en) | Rare earth permanent magnet material | |
| EP0249973B1 (en) | Permanent magnetic material and method for producing the same | |
| CN101859639A (en) | R-Fe-B series magnet of gradient resistance and production method thereof | |
| JP2018110162A (en) | Rare earth magnet and method for manufacturing the same | |
| JPH07105289B2 (en) | Rare earth permanent magnet manufacturing method | |
| JP2023047307A (en) | Rare earth magnetic material and method for manufacturing the same | |
| CN1649046A (en) | Forming method in magnetic field, and method for producing rare-earth sintered magnet | |
| AU609669B2 (en) | Method of manufacturing a permanent magnet | |
| CN1027473C (en) | Anticorrosive rare-earth-transition metal series magnet and method thereof | |
| US5447578A (en) | Corrosion-resistant rare earth metal-transition metal series magnets and method of producing the same | |
| JP2675430B2 (en) | Corrosion resistant rare earth-transition metal magnet and method of manufacturing the same | |
| JP3781094B2 (en) | Corrosion resistant rare earth magnet | |
| JP3647995B2 (en) | Powder for permanent magnet, method for producing the same and anisotropic permanent magnet using the powder | |
| WO2019107929A1 (en) | Method for manufacturing sintered magnet and sintered magnet | |
| EP4216239A1 (en) | A sintered ndfeb permanent magnet and preparation method thereof | |
| JP7303157B2 (en) | Rare earth magnet and manufacturing method thereof | |
| JPH0513207A (en) | Manufacture of r-t-b-based permanent magnet | |
| JPH0822909A (en) | Permanent magnet having sufficient mechanical strength | |
| CN1251203A (en) | Product with magnetic properties, method of its prepn. and magnet obtained from this product | |
| CN116313353B (en) | Neodymium-iron-boron magnet and preparation method thereof | |
| JPH0644526B2 (en) | Rare earth magnet manufacturing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C15 | Extension of patent right duration from 15 to 20 years for appl. with date before 31.12.1992 and still valid on 11.12.2001 (patent law change 1993) | ||
| OR01 | Other related matters | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |