CN1274394A - Permanent magnetic alloy with excellent heat resistance and process for producing same - Google Patents

Permanent magnetic alloy with excellent heat resistance and process for producing same Download PDF

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CN1274394A
CN1274394A CN 99801229 CN99801229A CN1274394A CN 1274394 A CN1274394 A CN 1274394A CN 99801229 CN99801229 CN 99801229 CN 99801229 A CN99801229 A CN 99801229A CN 1274394 A CN1274394 A CN 1274394A
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atom
excellent heat
magnet alloy
alloy
heat resistance
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CN1098368C (en
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鎌田雅美
尾畠道夫
佐藤祐一
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Dowa Holdings Co Ltd
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Dowa Mining Co Ltd
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    • H—ELECTRICITY
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    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
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    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
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    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
    • H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
    • H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
    • H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • C22C1/00—Making non-ferrous alloys
    • C22C1/04—Making non-ferrous alloys by powder metallurgy
    • C22C1/0433—Nickel- or cobalt-based alloys
    • C22C1/0441—Alloys based on intermetallic compounds of the type rare earth - Co, Ni
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • C22C33/00—Making ferrous alloys
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
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    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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    • C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
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    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
    • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
    • H01F1/047—Alloys characterised by their composition
    • H01F1/053—Alloys characterised by their composition containing rare earth metals
    • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
    • H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
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    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0266—Moulding; Pressing
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    • B22—CASTING; POWDER METALLURGY
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Abstract

A permanent magnetic alloy having excellent heat resistance which comprises 0.1 to 15 at.% C, 0.5 to 15 at.% B (the sum of C and B is 2 to 30 at.%), 0 to 40 at.%, excluding 0 at.%, Co, 0.5 to 5 at.% Dy and Tb, 8 to 20 at.% R (provided that R represents at least one element selected from the group consisting of Nd, Pr, Ce, La, Y, Gd, Ho, Er, and Tm), and Fe and unavoidable impurities as the remainder.

Description

The permanent magnet alloy of excellent heat resistance and manufacture method thereof
Even the present invention relates in atmosphere, use under 200 ℃ also deterioration, that thermotolerance is extremely good hardly R-B-C-Co-Fe based permanent magnet alloy (R is Y or rare earth element) of magnetic force.
As the rare earth magnet of excellent heat resistance, known have a Sm-Co magnet.But this magnet is a high price.Here said thermotolerance, the spy refers to magnetic force not Yin Re and deterioration.As more cheap and improved stable on heating rare earth magnet, have by same applicant and open the R-B-C-Co-Fe based permanent magnet alloy of record in the flat 4-116114 communique (speciallyying permit No. 2740981) the spy.This magnet alloy be with C (carbon) as necessary alloying element after, as R light rare earths class and heavy rare earths class are used in combination.In this communique, demonstrate that irreversible degaussing rate significantly improves when containing C (negative value is near 0% side), and pointed out, when the heavy rare earths dvielement was used for R a part of, irreversible degaussing rate further improved.
The occasion of permanent magnet is installed on machine that is provided with near pyrotoxin and so on, even require temperature rising magnetic force also not descend, it is not deterioration of residual flux density (Br), but (for example automobile is with near reaching 200 ℃ that machine that is provided with around the engine and so on has to reach near 200 ℃ occasion in the use temperature of magnet, in example, do not get rid of the Electric motor yet), then can only use over Sm-Co magnet in the product.But as previously mentioned, they are high prices.Common Nd-Fe (Co)-B based rare earth magnet then can not (for example 200 ℃) use under such high temperature.
Open the record of flat 4-116144 communique as above-mentioned spy with C (carbon) during as alloying element, owing to contain C, irreversible degaussing rate is improved, and when the part of R is used the heavy rare earths dvielement, irreversible degaussing rate further improves, even but do not demonstrate in this communique and be warmed up to 200 ℃ of also not degaussings.
Thereby, the objective of the invention is, even obtain the permanent magnet alloy of cheapness when 200 ℃ are used also tolerant excellent heat resistance down.
For solving above-mentioned each problem, the inventor is based on the spy and opens the C that contains that flat 4-116144 communique proposes and improve stable on heating basic understanding, then each heavy rare earths dvielement is investigated stable on heating influence, obtain following new discovery: except basic rare earth element such as Nd and Pr, when Dy that compound again interpolation is an amount of and Tb, when particularly adding Dy and Tb with the amount that interrelates, resistance toheat significantly improves.
That is, the invention provides a kind of permanent magnet alloy of excellent heat resistance, it consists of, in atomic percentage (atom %),
C:0.1～15 atom %
B:0.5～15 atom %
C+B:2～30 atom %
Co:40 atom % following (not containing 0%)
Dy+Tb:0.5～5 atom %
Preferred Tb (atom %)/Dy (atom %): 0.1～0.8,
R:8～20 atom %,
Wherein, R represents by Nd, Pr, and Ce, La, Y, Gd, Ho, Er, and at least a kind of the element of selecting in the group that Tm formed,
All the other: Fe and unavoidable impurities.
The thermotolerance of this permanent magnet alloy is 0%～-20% scope in the irreversible degaussing rate of calculating by following formula (1) (20 ℃), be more preferred from 0%～-15% scope, and (point shown in but the iHc 〉=13KOe) shows its feature.
Irreversible degaussing rate (200 ℃)=100 * (A 200-A 25)/A 25(1) wherein,
A 25: will be according to making magnetic diffusivity (Pc) become 1, the test portion of adjusting shape magnetizes under 50KOe, then the magnetic flux value of measuring down in room temperature (25 ℃).
A 200: will measure A 25 Test portion 200 ℃ keep 120 minutes after, the magnetic flux value that cool to room temperature (25 ℃) is measured.
To not be, the permanent magnet alloy of irreversible degaussing rate 0～-20%, can be by the suitable combination of Dy and Tb, Dy+Tb:0.5～5 atom % for example, and Dy is that 0.3～4.9 atom % and Tb are that the scope combination (scope that the some A of Fig. 1, B, C and D surround) of 0.1～4.7 atom % obtains, and then irreversible degaussing rate 0～-15% can be obtained by the Dy content of some B, C, H, E, F and scope that G surrounds shown in Figure 1 and Tb content.
Fig. 1 is that the magnet of table 2 is put the distribution plan of the irreversible degaussing rate of the 200 ℃ of following irreversible degaussing rate values of demonstration that obtain in order with the content of Dy and Tb.
Fig. 2 shows at making the spy open the magnet of flat 4-116144 communique embodiment 24 and the magnetized occasion of magnet of the embodiment of the invention 2 under 50KOe according to making magnetic diffusivity (Pc) become 3 test portions of adjusting shape, changes the figure that measures the fixed irreversible degaussing rate result of warm location survey.
Fig. 3 shows except using to become 1 according to magnetic diffusivity (Pc) and adjust like that the test portion of shape, carries out the figure of irreversible degaussing rate measurement result equally with Fig. 2.
The serviceability temperature of magnet is predetermined to reach 200 ℃ sometimes by situation, thus the occasion of planing machine and so on, and what become its design pointer is exactly irreversible degaussing rate under 200 ℃. That is, the value (negative value) of the irreversible degaussing rate (200 ℃) of above-mentioned (1) formula as far as possible near 0% for well.
When containing the addition of C in R represents the R-B-Co-Fe based sintered magnet alloy of Nd or Nd+Pr, the value (negative value) of irreversible degaussing rate (160 ℃) is close to 0. This fact shows in the embodiment of Unexamined Patent 4-116144 communique. But the irreversible degaussing rate (160 ℃) shown in this communique is with the A in above-mentioned (1) formula200Be replaced as A160Value (A160160 ℃ of maintenance magnetic flux value that cool to room temperature is measured after 120 minutes), and be that magnetic capacity (Pc) is 3 o'clock measured value. That is to say, be for the test portion that is 3 adjustment shapes by Pc, after the magnetization, measures A under 50KOe25And A160The irreversible degaussing rate (160 ℃) that reaches magnetic flux value and obtain. As by seeing in this communique, the effect (and oxidative resistance effect) that causes heat resistance to improve because containing C as can be known, but then be unclear for the irreversible degaussing rate under 200 ℃. In addition, for all R-(Fe, Co) of past-B based sintered magnet alloy (not with C as alloying element), then do not know to have irreversible degaussing rate (200 ℃) to demonstrate 0%～-20% situation.
The inventor is since proposing above-mentioned communique, in order more to improve the heat resistance of R-Fe-Co-C-B based sintered magnet alloy, composition and manufacture method for this alloy have been proceeded all experimental studies, discovery is having among several rare earth elements, when an amount of compound interpolation Dy and Tb, can obtain significantly low magnet alloy of irreversible degaussing rate. If add separately Dy and Tb, then almost can not see its effect, but in the two occasion of compound interpolation, it is good that heat resistance will become.
Below, the summary reason of each component content scope of restriction magnet alloy of the present invention and the manufacture method of alloy magnet of the present invention are described.
[C:1.1～15 atom %]
As Unexamined Patent 4-116144 communique is put down in writing, provide following effect: one side is kept the magnetic characteristic of this magnet alloy well, and a shortcoming in the face of rare earth magnet is that easily oxidizable matter is carried out modification. Oxidative resistance is improved. But also give the reduction of irreversible degaussing rate. C raising oxidative resistance and stable on heating effect are insufficient when less than 0.1 atom %. But Br is reduced. Therefore, C content is 0.1～15 atom %, but preferred C amount is the scope of 1.0～10 atom %, and better C amount is the scope of 2.5～7 atom %.
[B:0.5～15 atom %]
B is necessary for forming Magnetic Phase, therefore 0.5 atom % must be arranged at least, but can make magnetic characteristic deteriorated during excessive adding. Therefore B content is 0.5～15 atom %, but preferred B amount is the scope of 1.0～10 atom %, and better B amount is the scope of 1.5～7 atom %.
[C+B:2～30 atom %]
For the generation of Magnetic Phase and the raising of oxidative resistance, C+B contains 2 atom % at least. If but surpass 30 atom %, then make magnetic characteristic deteriorated, therefore C+B is decided to be 2～30 atom %.
[Co:40 atom % is following]
Co has one side and keeps the effect that magnetic characteristic simultaneously improves curie point. Therefore must contain Co, if but surpass 40 atom %, then coercitive reduction is remarkable, so content is below 40 atom %.
[Dy+Tb:0.5～5 atom %]
Dy and Tb are the characteristic elements of magnet of the present invention, by compound interpolation two elements, can significantly reduce irreversible degaussing rate. Therefore, must be more than 0.5 atom % as the total amount of Dy+Tb, still, even its total amount surpasses 5 atom %, the effect that heat resistance improves is also saturated, can make on the contrary magnetic characteristic deteriorated, therefore this total is measured and makes 0.5～5 atom %. In addition, when adding separately Dy or adding Tb separately, shown in the comparative example, give hardly the reduction of irreversible degaussing rate as described later. Thinking thus, is because the synergy of two elements reduces irreversible degaussing rate. In addition, two elements to contain proportional Tb (atom the %)/scope of Dy (atom %) 0.1～0.8 be good, as described later shown in the embodiment, if Dy is 0.3～4.9 atom %, Tb is the scope of 0.1～4.7 atom %, then can access the magnet of excellent heat resistance, it demonstrates, and the irreversible degaussing rate in the time of 200 ℃ is 0～-20% in the situation of magnetic capacity=1, preferably 0～-15%.
[R:8～20 atom %]
As the rare earth element beyond Dy and the Tb, contain one or two or more kinds 8～20 atom % of Nd, Pr, Ce, La, Y, Gd, Ho, Er, Tm, can in the sintered magnet alloy, form Magnetic Phase and Grain-Boundary Phase by this, keep high iHc and Br. In these R elements, particularly preferred element is Nd and Pr, and Nd or compound interpolation Nd and Pr are added separately in special hope. During R less than 8 atom %, can not get sufficient Br, when surpassing 20 atom %, also can not get sufficient Br. Preferred R constituent content is 13～18 atom %.
The one-tenth of going up thus is grouped into the permanent magnet alloy of the present invention of formation, irreversible degaussing rate (200 ℃) by above-mentioned (1) formula, can have 0～-20%, better 0～-15% low value even 0～-5% value, as rare earth magnet, provide the permanent magnet alloy of high-temperature use primary except Sm-Co. So far for containing the B rare earth magnet, countermeasure is the degaussing that pre-determines when heating up, then uses to have high coercitive permanent magnet, even but because heating up, magnet of the present invention also causes hardly degaussing, therefore as the original permanent magnet of high magnetic force, its function can continue. Particularly magnet of the present invention as long as iHc is more than the 13KOe, more than the preferred 15KOe, even then use, also can be kept magnetic characteristic in the intensification purposes. The magnet in past is for to keep magnetic characteristic in the intensification purposes, must use to have quite high iHc, if in comparison, can be described as is effective permanent magnet alloy.
When making permanent magnet alloy of the present invention, can adopt melting, casting, pulverizing, shaping, a series of operation of agglomerating to make sintered magnet.As the melting and casting method, can adopt vacuum melting casting, inert gas atmosphere melting and casting method, emergency cooling roll method, atomization etc.For producing the sintered magnet of magnetic properties and excellent heat resistance, between casting process and pulverizing process, insert heat treatment step, raw material before pulverizing is heat-treated to good in the temperature more than 600 ℃ in inert atmosphere, take this further to reduce irreversible degaussing rate.In addition, carry out sintering under 1000～1200 ℃ the temperature in sintering circuit in rare gas element, by this sintering temperature slow cooling to 600～900 ℃, it is good then carrying out chilling by this temperature again.By the chilling behind this sintering, can further reduce irreversible degaussing rate.
Chilling behind above-mentioned thermal treatment and sintering can be made sintered magnet alloy of the present invention according to opening the same method of putting down in writing in the flat 4-116144 communique of sintered magnet with the spy handling.Its summary is as follows.
At first, will in vacuum melting furnace, carry out melting more than 1600 ℃, chilling casting in water-cooled mold then by the raw material of each composition of alloy composition weighing.With the ingot bar thermal treatment in Ar atmosphere more than 600 ℃ as described above that obtains, use the jaw crusher coarse reduction then.Use the vibromill micro mist broken the meal that obtains again, make the powder of median size 2～10 μ m.These powder-grinding process are also carried out in Ar atmosphere.And can in the broken operation of the latter's micro mist, add the C part of raw materials.That is, the C part of raw materials drops into vacuum melting furnace, and then rest part adds in the broken operation of this micro mist.As this C raw material, carbon black suits, and also can use but aliphatic hydrocarbon, higher fatty acid system alcohol, higher fatty acid, fatty acid amide, metallic soap, fatty acid ester etc. contain the organic substance of C.
Then with this powder externally in the magnetic field press-powder be shaped.Compacting pressure is at 1～5t/cm 2Scope, external magnetic field be to suit more than the 15KOe.This forming process also wishes to carry out in Ar atmosphere.This molding is carried out about 2 hours sintering under 1000～1200 ℃ in Ar atmosphere.Then, send out aforementioned, then by this temperature chilling by sintering temperature slow cooling to 600～900 ℃.For beginning chillings by 600～900 ℃, can adopt by the method for this temperature winding-up low temperature rare gas element, water or oil or with its similar liquid in the method for flooding carry out, but preferably begin 600～900 ℃ of temperature by this chilling, be quenched to 400 ℃ with the above speed of cooling of above, preferred-100 ℃/min of-50 ℃/min, or below it.
Thereby, the invention provides a kind of manufacture method of permanent magnet alloy of excellent heat resistance, each raw material melting and casting with alloying constituent, the alloy of gained is pulverized, this powder press-powder is shaped, this molding is carried out sintering under 1000～1200 ℃ temperature in rare gas element, make the sintered magnet alloy that mentioned component is formed, it is characterized in that, alloy before pulverizing is heat-treated in the temperature rare gas element more than 600 ℃, and/or in rare gas element behind 1000～1200 ℃ the sintering temperature, by this sintering temperature slow cooling to 600～900 ℃, carry out chilling then.Wherein, the C part of raw materials can be added when the melting, the other parts of C raw material are added when alloy is pulverized.
Below enumerate the representational embodiment of magnet of the present invention.
Embodiment
Embodiment 1
Adopt the method manufacturing of following narration to have the alloy that following ingredients is formed.
The one-tenth of＜alloy is grouped into (atom %) 〉
C:5.0 atom %,
B:1.8 atom %,
Co:12.0 atom %,
Nd:13.0 atom %,
Dy:2.5 atom %,
Tb:0.5 atom %,
Fe:65.2 atom %,
C+B=6.8 atom %,
Dy+Tb=3.0 atom %,
Tb/Dy＝0.2
＜manufacture method 〉
Measure each composition raw material, melting in vacuum melting furnace by above-mentioned alloy composition.Wherein, the C part of raw materials does not drop in this smelting furnace and is preserved.The liquation of gained is cast by 1600 ℃ of chillings in the copper water-cooled mold, obtained the ingot bar alloy.This ingot bar alloy is heat-treated or do not heat-treated in the Ar atmosphere under the temperature shown in the table 1, use the jaw crusher coarse reduction, the above-mentioned C raw material input vibromill of this meal and preservation is pulverized, obtain the powder of median size 5 μ m.
With this powder pressure 2t/cm 2Magnetic forming in the 15KOe of external magnetic field, with this molding in Ar atmosphere in 1100 ℃ of sintering 2 hours, begin temperature by this sintering temperature slow cooling to the chilling shown in the table 1 then, begin temperature by this chilling and carry out chilling with the speed of cooling shown in the table with the method for winding-up Ar.Estimate magnetic properties, thermotolerance and the scale resistance of gained sinter, it be the results are shown in table 1.Carry out thermotolerance and scale resistance evaluation as follows.
＜thermotolerance evaluation 〉
The mensuration of the irreversible degaussing rate in the time of (1) 200 ℃
According to magnetic diffusivity (Pc) is that 1 pair of test portion carries out shape adjustments.Be exactly the test portion that cuts out 2.5mm * 2.5mm * 1.05mm specifically.
This test portion is magnetized in the external magnetic field of 50KOe, measure magnetic flux down in room temperature (25 ℃).The mensuration of this magnetic flux is to adorn iron-core coil to carry out on the maxwellmeter of Japan magnetism Industrial Co., Ltd system.The magnetic flux value of this moment is defined as A 25
Then, should keep 120 minutes down at 200 ℃ by magnetized material.This heating remains in the oil bath of filling silicone oil to be carried out.The temperature precision of oil bath controls to ± and 0.1 ℃, at room temperature fully after the cooling, measure magnetic flux once more by the test portion that takes out in the oil bath with above-mentioned maxwellmeter.The magnetic flux value of this moment is defined as A 200By the A that measures 25And A 200Calculate irreversible degaussing rate with following formula.
Irreversible degaussing rate (200 ℃) (%)=100 * (A 200-A 25)/A 25
The mensuration of the irreversible degaussing rate in the time of (2) 160 ℃
The embodiment that opens flat 4-116144 communique with the spy is same, is that 3 pairs of test portions carry out shape adjustments according to magnetic diffusivity, and except heating that will be in oil bath kept being taken as 160 ℃ * 120 minutes, the mensuration during with above-mentioned 200 ℃ was same, measures A 25And A 160, calculate irreversible degaussing rate by preceding formula.
(3) magnetic properties and coercitive temperature factor
After test portion magnetized in the external magnetic field of 50KOe, the magnetic properties when measuring room temperature (25 ℃) with oscillating mode magnetometry device.About coercitive temperature factor, the coercive force during with room temperature is defined as Bo, the tailor-made B of coercive force that measures 160 ° ℃ the time with same oscillating mode magnetometry device 1, calculate by following formula again.
Coercitive temperature factor (%/℃)
＝100×(B 1-B 0)/B 0/(160-25)
(4) mensuration of scale resistance
Measure the carrying out of getting rusty with pressure cooking test (PCT).Be exactly to keep 100 hours the generation that visual observation is become rusty at this moment down specifically at 120 ℃, 2 normal atmosphere, 100%RH (saturation conditions).
Embodiment 1 Create conditions ??Br ??(KG) ??iHc ??(KOe) BHmax (GOe) Irreversible degaussing rate % Coercitive temperature factor %/℃ Have rustless during PCT
The thermal treatment temp of casting alloy ℃ Chilling during sintering begins temperature ℃ Begin the speed of cooling of temperature to 400 ℃ by chilling ??200℃ ??Pc＝1 ??160℃ ??Pc＝3
??a ??800 ??900 ??-100 ℃/min ????12 ????17 ????34 ????-3 ????-0.7 ??-0.32 Do not have
??b No thermal treatment ??900 ??-100 ℃/min ????12 ????17 ????32 ????-10 ????-1.2 ??- Do not have
??c ??800 ??1100 ??-100 ℃/mmin ????12 ????17 ????33 ????-9 ????-1.0 ??- Do not have
??d ??800 Slow cooling is to room temperature Average 5 ℃/min is to room temperature ????12 ????10 ????25 ????-20 ????-1.5 ??- Do not have
As shown in Table 1, obtained irreversible degaussing rate (200 ℃) for-3% permanent magnet alloy (for example table 1 a).And the irreversible degaussing rate (160 ℃) of a alloy is-0.7%, almost approaches 0.Thereby, even under high-temperature use, also can keep high magnetic force.
See again and create conditions that for example if a and b are compared then and can find out, when carrying out the thermal treatment of ingot bar, irreversible degaussing rate changes.In addition, as can be known, if carrying out chilling by the temperature more than at least 700 ℃ behind the sintering, then coercive force improves, and irreversible degaussing rate also reduces when comparing a and c and d.
＜embodiment 2～16 and comparative example 1～6 〉
Except the one-tenth with alloy is grouped into by changing like that shown in the table 2, adopt the same manufacturing sintered part of creating conditions of a with embodiment.Measure the characteristic of gained sintered magnet similarly to Example 1, its result is remembered in the lump in table 2.
Example No. Alloy composition (atom %) ??Br ??(KG) ???iHc ???(KOe) ??BH ??max ??(MGOe) Irreversible degaussing rate % Coercitive temperature factor %/℃ Have or not during PCT and get rusty
??C ??B ??Dy ??Tb ????Nd ??Co ??Fe ???DY+Tb ???Tb/Dy ??200℃ ??Pc＝1 ??160℃ ??Pc＝3
Embodiment 2 ?5.0 ?1.8 ?2.5 ?1.0 ????13.0 ??12.0 ??64.7 ????3.5 ????0.4 ?11.0 ????17 ????31 ????-4 ????-0.7 ????-0.26 Do not have
Embodiment 3 ?4.0 ?3.0 ?2.5 ?0.5 ????13.0 ??12.0 ??65.0 ????3.0 ????0.2 ?12.0 ????17 ????32 ????-5 ????-0.8 ????-0.27 Do not have
Embodiment 4 ?5.0 ?1.8 ?3.5 ?0.4 ????13.0 ??12.0 ??64.3 ????3.9 ????0.1 ?11.5 ????17 ????30 ????-7 ????-0.9 ????-0.28 Do not have
Embodiment 5 ?5.0 ?1.8 ?0.4 ?0.3 ????13.0 ??12.0 ??67.0 ????0.7 ????0.8 ?13.5 ????13 ????38 ????-20 ????-1.5 ????-0.42 Do not have
Embodiment 6 ?5.0 ?1.8 ?3.8 ?0.7 ????15.0 ??12.0 ??61.7 ????4.5 ????0.2 ?11.5 ????17 ????28 ????-7 ????-0.9 ????-0.29 Do not have
Embodiment 7 ?3.5 ?1.0 ?2.5 ?0.5 ????13.0 ??12.0 ??67.5 ????3.0 ????0.2 ?12.0 ????17 ????33 ????-10 ????-1.2 ????-0.31 Do not have
Embodiment 8 ?5.0 ?1.8 ?2.5 ?0.5 ????10.0 ??6.0 ??71.2 ????3.0 ????0.2 ?11.5 ????16 ????33 ????-8 ????-1.0 ????-0.32 Do not have
??P＝3.0
Embodiment 9 ?4.0 ?2.5 ?2.5 ?0.5 ????12.0 ??12.0 ??66.5 ????3.0 ????0.2 ?12.7 ????17 ????38 ????-8 ????-1.0 Do not have
Embodiment 10 ?4.0 ?2.5 ?3.0 ?0.5 ????12.0 ??12.0 ??66.0 ????3.5 ????0.2 ?12.5 ????17 ????34 ????-11 ????-1.0 Do not have
Embodiment 11 ?4.0 ?3.0 ?2.5 ?0.5 ????12.5 ??12.0 ??65.5 ????3.0 ????0.2 ?12.6 ????17 ????36 ????-8 ????-0.9 Do not have
Embodiment 12 ?5.0 ?1.8 ?1.0 ?0.5 ????13.0 ??12.0 ??66.7 ????1.5 ????0.5 ?13.0 ????14 ????35 ????-15 ????-1.1 Do not have
Embodiment 13 ?5.0 ?1.8 ?2.0 ?1.0 ????13.0 ??12.0 ??65.2 ????3.0 ????0.5 ?11.9 ????17 ????31 ????-12 ????-1.0 Do not have
Embodiment 14 ?5.0 ?1.8 ?1.5 ?2.0 ????13.0 ??12.0 ??64.7 ????3.5 ????1.3 ?11.8 ????17 ????29 ????-18 ????-1.4 Do not have
Embodiment 15 ?5.0 ?1.8 ?1.0 ?3.0 ????13.0 ??12.0 ??64.2 ????4.0 ????3.0 ?11.4 ????17 ????28 ????-20 ????-1.7 Do not have
Embodiment 16 ?5.0 ?3.5 ?0.5 ?2.0 ????13.0 ??12.0 ??64.0 ????2.5 ????4.0 ?12.3 ????17 ????34 ????-19 ????-1.4 Do not have
Comparative example 1 ?5.0 ?1.8 ?0 ?0 ????15.0 ??10.0 ??68.2 ????0 ????- ?14.2 ????7 ????41 ????-95 ????-20.0 ????* Do not have
Comparative example 2 ?5.0 ?1.8 ?0.5 ?0 ????14.0 ??12.0 ??66.7 ????0.5 ????0 ?14.0 ????10 ????42 ????-95 ????-3.0 ????* Do not have
Comparative example 3 ?5.0 ?1.8 ?3.0 ?0 ????13.0 ??12.0 ??65.2 ????3.0 ????0 ?12.0 ????15 ????33 ????-32 ????-1.5 ????-0.59 Do not have
Comparative example 4 ?5.0 ?1.8 ?0 ?0.5 ????13.6 ??11.5 ??67.6 ????0.5 ????- ?13.7 ????7 ????40 ????-91 ????-21.0 ????* Do not have
Comparative example 5 ?0.1 ?3.5 ?2.5 ?0.5 ????13.0 ??10.0 ??70.4 ????3.0 ????0.2 ?12.0 ????17 ????32 ????-12 ????-1.0 ????-0.39 Give birth to the some rust
Comparative example 6 ?4.0 ?1.8 ?0 ?3.0 ????13.0 ??12.0 ??66.2 ????3.0 ????- ?12.7 ????16 ????33 ????-30 ????-1.5 Do not have
*) coercitive change is remarkable, can not correctly measure
As shown in Table 2, the irreversible degaussing rate when adding the two 2～16,200 ℃ of embodiment of Dy and Tb is all low, and the irreversible degaussing rate 160 ℃ the time also nearly all approaches 0.In addition, coercitive temperature factor is also low, and scale resistance is also good.
In contrast, do not add Dy and Tb comparative example 1,0.5 atom %Dy is arranged but do not add the comparative example 2 of Tb and do not add Dy but the comparative example 4 of 0.5 atom %Tb is arranged, irreversible degaussing rate in the time of 200 ℃ is-95% ,-95% and-91%, almost completely loses magnetic force when being warmed up to 200 ℃.That is to say that a kind of irreversible degaussing rate during to 200 ℃ of only adding Dy and Tb is display effect not.In addition, shown in comparative example 3, if add Dy and its content height separately, reducing though then irreversible degaussing rate has to a certain degree, also is inadequate.In addition, the C of comparative example 5 amount is lower than the scope of the present invention's regulation, so scale resistance is poor.Comparative example 6 is not add Dy but add 3.0 atom %Tb, though to compare thermotolerance good with comparative example 4, the irreversible degaussing rate in the time of 200 ℃ is low to reach-30%.
It is Dy content (atom %) that Fig. 1 gets transverse axis, the longitudinal axis is Tb content (atom %), at whole magnets (but except comparative example 5 that a bit rust takes place) of table 2, with the Dy and the Tb amount that contain separately, which kind of level is the value of the irreversible degaussing rate when having demonstrated 200 ℃ be distributed on.The value of the irreversible degaussing rate of diagrammatic numeric representation when 200 ℃ of this position among Fig. 1.
Result by Fig. 1 can learn that at Dy:2～3 atom %, in the zone of Tb:0.3～1.5 atom %, there is peak value (irreversible degaussing rate approaches 0 point) in 200 ℃ irreversible degaussing rate.More specifically say and be exactly, irreversible degaussing rate in the time of 200 ℃ is shown as 0～-20% zone, be in the intersection point of straight line (1) (2) (3) (4) (5) (6), scope by an A, B, C and D encirclement, and the irreversible degaussing rate 200 ℃ the time is shown as 0～-15% zone, is the scope that a B, C, H, E, F and G surround.
In addition, straight line (1)～(6) are represented with following formula.
Straight line (1): Dy=0.3
Straight line (2): Tb+Dy=0.5
Straight line (3): Tb=0.1
Straight line (4): Tb=0.1Dy
Straight line (5): Tb=0.8Dy
Straight line (6): Tb+Dy=5.0
In addition, the coordinate (Dy atom %, Tb atom %) of some A～H is as follows.
Point A (0.3,4.7)
Point B (0.3,0.2)
Point C (0.4,0.1)
Point D (4.9,0.1)
Point E (4.5,0.50)
Point F (2.8,2.2)
Point G (0.3,0.24)
Point H (1.0,0.1)
What Fig. 2 showed is, the spy is opened the magnet that sees embodiment 24 of thermotolerance the best in the disclosed embodiment magnet of flat 4-116144 communique, magnet with the embodiment of the invention 2, being test portion magnetized occasion under 50KOe of 3 adjustment shapes, change the result who measures the irreversible degaussing rate of temperature measuring by magnetic diffusivity (Pc).Fig. 3 has shown the irreversible degaussing rate that is similar to Fig. 2, will be test portion magnetized occasion under 50KOe of 1 adjustment shape by Pc only, changes the result who measures the irreversible degaussing rate of temperature measuring.The magnet of Te Kaiping 4-116144 communique embodiment 24 (being called openly magnet) is stated as the composition with 9Nd-9Dy-59Fe-15Co-1B-7C in this communique, 160 ℃ irreversible degaussing rate is-1.0% during Pc=3.
As shown in Figure 2, press the test portion that Pc=3 adjusts shape, the irreversible degaussing rate in the time of 160 ℃ openly magnet is-1.0%, and the magnet of the embodiment of the invention 2 is-0.7%, almost can not manifest difference.But, during with Pc=3 200 ℃ irreversible degaussing rate openly magnet contrast for-12.9%, the magnet of the embodiment of the invention 2 brings up to-1.9%.Such tendency use by Pc be 1 adjust show among Fig. 3 of shape further clear and definite.That is, during Pc=1,160 ℃ irreversible degaussing rate openly magnet is-9.4%, in contrast, 2 of the embodiment of the invention bring up to-1.7%, about 200 ℃ irreversible degaussing rate, openly magnet is-22.3%, and in contrast, the embodiment of the invention 2 brings up to-0.4%.
As mentioned above, according to the present invention, obtained permanent magnet alloy that do not reach so far, that possess excellent heat resistance and scale resistance in the field of R-Fe (Co)-B series magnet.Thereby, as the permanent magnet that is contained on the machine that prediction can heat up, can provide the material of a kind of cheapness and excellent in magnetic characteristics.

Claims (12)

1. the permanent magnet alloy of excellent heat resistance is characterized in that, it is composed as follows:
C:0.1～15 atom %
B:0.5～15 atom %
C+B:2～30 atom %
Co:40 atom % following (not containing 0%)
Dy+Tb:0.5～5 atom %
R:8～20 atom %, wherein, at least a kind of element selecting in the group that R represents to be made up of Nd, Pr, Ce, La, Y, Gd, Ho, Er and Tm,
All the other: Fe and unavoidable impurities.
2. the permanent magnet alloy of the described excellent heat resistance of claim 1 is characterized in that, Tb (atom %)/Dy (atom %) is 0.1～0.8.
3. the permanent magnet alloy of claim 1 or 2 described excellent heat resistances is characterized in that, C is 1-10 atom %.
4. the permanent magnet alloy of claim 1,2 or 3 described excellent heat resistances is characterized in that, R is independent Nd, or Nd and Pr.
5. the permanent magnet alloy of claim 1,2,3 or 4 described excellent heat resistances is characterized in that, its iHc is more than the 13KOe.
6. the R-B-C-Co-Fe based sintered magnet alloy of the described excellent heat resistance of claim 1 is characterized in that, is in 0%～-20% scope by the irreversible degaussing rate of following (1) formula, but iHc 〉=13KOe
Irreversible degaussing rate (200 ℃)=100 * (A 200-A 25)/A 25(1)
Wherein:
A 25: will be that 1 test portion of adjusting shape is after magnetization under the 50KOe, in the following magnetic flux value of measuring of room temperature (25 ℃) by magnetic diffusivity (Pc).
A 200: will measure A 25Test portion 200 ℃ keep 120 minutes after, the magnetic flux value that cool to room temperature (25 ℃) is measured.
7. the R-B-C-Co-Fe based sintered magnet alloy of the described excellent heat resistance of claim 6 is characterized in that, Dy is 0.3～4.9 atom %, and Tb is 0.1～4.7 atom %, and 200 ℃ irreversible degaussing rate is 0～-20%.
8. the R-B-C-Co-Te based sintered magnet alloy of the described excellent heat resistance of claim 6, it is characterized in that, the content of Dy and Tb (atom %) is in the scope that some B, C, H, E, F and G shown in Figure 1 are surrounded, and 200 ℃ irreversible degaussing rate is 0～-15%.
9. the R-B-C-Co-Fe based sintered magnet alloy of the described excellent heat resistance of claim 2 is characterized in that, irreversible degaussing rate (200 ℃) is in 0%～-5% scope.
10. the manufacture method of the permanent magnet alloy of excellent heat resistance, each raw material melting and casting with alloying constituent, the alloy of gained is pulverized, this powder press-powder is shaped, with this molding in rare gas element in 1000～1200 ℃ sintering temperature, make the sintered magnet alloy that following ingredients is formed, it is characterized in that, alloy before the above-mentioned pulverizing is heat-treated in rare gas element under the temperature more than 600 ℃
The one-tenth of sintered magnet alloy is grouped into:
C:0.1～15 atom %
B:0.5～15 atom %
C+B:2～30 atom %
Co:40 atom % following (not containing 0%)
Dy+Tb:0.5～5 atom %
R:8～20 atom %,
Wherein, at least a kind of element selecting in the group that R represents to be made up of Nd, Pr, Ce, La, Y, Gd, Ho, Er and Tm,
All the other: Fe and unavoidable impurities.
11. the manufacture method of the described permanent magnet alloy of claim 10 is characterized in that, behind 1000～1200 ℃ sintering temperature, by this sintering temperature slow cooling to 600～900 ℃, carries out chilling then in rare gas element.
12. the manufacture method of claim 10 or 11 described permanent magnet alloys is characterized in that, when melting, add the C raw material-part, the other parts of interpolation C raw material when alloy is pulverized.
CN99801229A 1998-07-29 1999-07-28 Permanent magnetic alloy with excellent heat resistance and process for producing same Expired - Fee Related CN1098368C (en)

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