The application is to be that August 28, application number in 1998 are dividing an application of 98812729.6 application for a patent for invention the applying date.
The best mode that carries out an invention
SEM diffraction electron micrograph at representational tissue of the present invention shown in Fig. 1 and Fig. 2.That present grey in Fig. 1 and Fig. 2 is R for matrix mutually
2T
14The B phase, presenting the thin-line-shaped of light/dark balance is sheet α Fe phase mutually.And most somber color dots is to form dendritic R in Fig. 2
2T
17Phase, most pitch black points are dendroid α Fe phases.Be in dendroid R
2T
17Mutually and near the white point of the majority of dendroid α Fe mutually be the rich R phase of formation because Compositional balance is destroyed.
The principal phase that constitutes the R-T-B sintered magnet production of raw material for use alloy of the general known tissue that uses is the R as matrix
2T
14B phase, the rich R phase of sheet and rich B are mutually.In addition also often form dendroid α Fe phase.Forming this phase time, Compositional balance is destroyed, near the rich R phase of formation this phase.The SEM diffraction electron micrograph of known tissue shown in Figure 3.That present grey in Fig. 3 is R as matrix mutually
2T
14The B phase, what present white wire is the rich R phase of sheet mutually.In addition, Duo Shuo pitch black point is a dendroid α Fe phase.The white point that is near the majority of dendroid α Fe mutually is the rich R phase of the formation because Compositional balance is destroyed.
The fusing point of rich R phase is about 660 ℃, from behind the casting solidification to 660 ℃ cooling rate under the slow situation or when heat-treating more than 660 ℃, the rich R of sheet on the way is cut off mutually, and is tending towards the circle shape.In this manual, the rich R that changes like this of shape also regards sheet mutually as.
Can conclude that from the comparison of Fig. 1 and Fig. 2 and Fig. 3 principal phase of the present invention is that the R-T-B sintered magnet production of raw material for use alloy organizing of alloy organizing and the general known tissue that uses has tangible different.
In principal phase of the present invention is in the alloy, and the R composition is R
2T
14Below the R composition of B phase, the rich R of sheet as seeing in known tissue because the deficiency of R composition does not exist in fact, forms as sheet the Fe composition of R composition relative surplus mutually mutually.Its formation amount is R forming the zone
2T
14The total of the sheet α Fe phase that disperse forms in the 1st zone of B phase matrix and the matrix in the 1st zone is more than the 5 volume %.
On the other hand, about to the harmful dendroid α Fe of the productivity ratio of sintered magnet and magnetic mutually, it forms the zone (that is, at R
2T
14The total in dendroid α Fe phase that disperse forms in the 1st zone of B phase matrix and the 1st zone of matrix) is below the 10 volume %, is more preferably below the 5 volume %, preferably 0 volume %.The zone that the dendritic α Fe of if tree forms mutually surpasses 10 volume %, and the comminuted of raw alloy just reduces significantly, in the reason of the component fluctuation when becoming pulverizing, causes that magnetic reduces or the increase of fluctuation.
The assay method in the zone that zone that sheet α Fe forms mutually or dendroid α Fe form mutually, volume % and area % can be used as and be equal to, therefore for example have and utilize SEM diffraction electronic image that the fractography of alloy is taken the photograph into photo, the method for using image processing apparatus to obtain.Just, because the state of tissue depends on that the position of observation can be different, so select any part of section more than 10, utilize SEM diffraction electronic image to take the photograph into photo, obtain the total area in the zone that zone that total and the sheet α Fe of the cross-sectional area of observation form mutually or dendroid α Fe form mutually, can obtain both ratios.
Principal phase of the present invention is the middle mutually R of the formation of alloy
2T
17In the manufacture process of sintered magnet, do not cause problems such as crush efficiency reduction.In addition, be soft phase on this phase magnetic, just reduce coercive force and rectangularity in the sintered magnet if be present in.But, if the crystal-boundary phase alloy that will suit to form and this principal phase are the mangcorn sintering of alloy, when sintering, just disappear, be no problem therefore.
Then, illustrate that principal phase of the present invention is the manufacture method of alloy.In the alloy that causes with common die cast legal system, form harmful dendroid α Fe phase in its most zone.In order to suppress the formation of such dendroid α Fe phase, must be to solidify than the fast cooling rate of die cast method in the past, for example the Strip casting method is suitable.This method can be cast the thin plate of the about 0.1~0.5mm of average thickness, therefore solidifies with the cooling rate faster than die cast method in the past and carries out.Single-roller method and double roller therapy are arranged in the Strip casting method, can select any method, but device is simple, the also easy single-roller method of the control of operating condition is suitable.And then, in order to make the setting rate on the roller fast, can make being in the big He atmosphere of thermal conductivity of roller on every side.Principal phase of the present invention is that the manufacture method of alloy is not limited to the Strip casting method, can suitably select to form the manufacture method of tissue of the present invention.
Be used to form the composition that principal phase of the present invention is an alloy organizing, R is made up of Nd, Pr, Dy in fact, and the total of its content is 10~11.8 atom %, wherein contains the Dy of 1~6 atom %, and the content of B is 5.88~8.00 atom %, and all the other are made up of T.
During more than 11.8 atom %, form the rich R phase of sheet of easy oxidation at R.And when R was less than 10 atom %, even the fast method of cooling rate after utilizing image-tape material casting to cast is like that cast, also volume ground formed dendroid α Fe phase, it can not be formed the zone and be suppressed at below the 10 volume %.Therefore the content of R is limited to 10~11.8 atom %.
Dy is difficult to form dendroid α Fe phase, and it is important therefore containing Dy in the present invention.If Dy content is reached more than the 1 atom %, the zone that forms dendroid α Fe phase is reached below the 10 volume %.And if Dy content is many, just be difficult to form dendroid α Fe phase all the more, but Dy is a high price, and,, is defined in below the 6 atom % from the viewpoint of reality because reduce the magnetization of sintered magnet.Because above reason, the content of Dy is defined in 1~6 atom %.Dy has the big magnetic field of anisotropy, and coercive force uprises in containing the sintered magnet of Dy.Therefore, be applicable to according to sintered magnet of the present invention and rise to high temperature and owing to be exposed to the motor that needs high-coercive force in the demagnetizing field.
About B, if be less than 5.88 atom %, just form dendroid α Fe phase in large quantities, making it form the zone can not be below 10 volume %.In addition, as crystal-boundary phase alloy when using the R-T do not contain B to be alloy, though make crystal-boundary phase alloy and principal phase be alloy mix proportion how, cooperate form in B all be not enough, have R soft on the magnetic behind the sintering
2Fe
17Phase, coercive force and rectangularity reduce.On the other hand, the content of B is many more, is difficult to form dendroid α Fe phase more.But, if the content of B surpasses 8.00 atom %,, forming R and measure considerable sintered magnet to be that non magnetic rich B almost is 0 mix proportion mutually behind the sintering, residual magnetic flux density reduces.In addition,, become the mix proportion of lacking some slightly with the R content behind the sintering in order to improve with the magnetic domain magnetic flux density, the rich B phase of residual volume behind sintering, residual magnetic flux density still reduces.Therefore principal phase is that the B of alloy is limited to 5.88~8.00 atom %.
About the composition of crystal-boundary phase alloy of the present invention, R must contain more than the 15 atom %.If the R of crystal-boundary phase alloy is less than 15 atom %, form α Fe phase easily.In addition, when being the alloy mixing with the many principal phases of B content, can avoid the B deficiency in the composition of sintered magnet, mixed R composition tails off.The oxygen concentration of allowing in order to ensure good magnetic became low for this reason, therefore can not make the sintered magnet of good magnetic on reality.Thereby R must contain more than the 15 atom % in crystal-boundary phase alloy.
As crystal-boundary phase alloy, can mix R-T and be alloy and R-T-B and be in the alloy a kind or 2 kinds and use.
Crystal-boundary phase alloy of the present invention can be utilized common die cast method, centre spinning (for example, the spy opens flat 8-296005), Strip casting manufactured.About utilizing which kind of method to make, can be according to comprising that the efficiency in the pulverizing such as hydrogen embrittlement pulverizing or the economy of relevant manufacturing select aptly.
The principal phase that makes as above is after alloy and crystal-boundary phase alloy are mixed, and carries out sintering and forms magnet.The mix proportion of this moment, principal phase is that alloy is more than the 60 weight %, crystal-boundary phase alloy is below the 40 weight %.Separately cooperation principal phase be alloy less than 60 weight %, when crystal-boundary phase alloy surpasses 40 weight %, it is many that the R that sintered magnet contains becomes, thereby residual magnetic flux density reduces.Therefore, must to make principal phase be alloy with more than the 60 weight %, crystal-boundary phase alloy to be to cooperate below the 40 weight %.
Co has and improves corrosion proof effect, and is therefore many and preferably contain Co more than the 1 atom % in crystal-boundary phase alloy oxidation easily at the R composition.By containing the Co more than the 1 atom %, form chemically stable R
3(FeCo), the oxidation in the time of therefore can suppressing the sintered magnet manufacturing.And with principal phase be that alloy mixes and in the sintered magnet made, also by containing Co, improves coercive force temperature characterisitic and corrosion resistance.But during less than 1 atom %, these effects are little at Co content.
Principal phase is alloy and crystal-boundary phase alloy, through the hydrogen embrittlement pulverizing, at N
2Utilize in the inert gases such as gas or Ar gas Blang's formula (Brown) pulverizing mill be crushed to the following middle pulverizing of about 0.5mm, at N
2Utilize the injecting type pulverizing mill in the inert gases such as gas or Ar gas and utilize the micro mist of ball mill or vertical ball mill etc. broken in organic solvent, micro mist is broken to 2~5 μ m in utilizing Fischer (Fisher) type microscreening device (FSSS) mensuration.When carrying out hydrogen embrittlement when pulverizing, the shape of former state that can band is implemented, but wishes coarse crushing to 10mm, makes the metal surface expose the back and implements.
In this crushing process, do not implement hydrogen embrittlement and pulverize, carry out coarse crushing after, can directly carry out middle pulverizing.In addition, if selected suitable hydrogen embrittlement pulverization conditions, pulverizing in just can not implementing, it is broken directly to carry out micro mist.
About principal phase is the mixing of alloy and crystal-boundary phase alloy, and can implement in which kind of crushing process such as coarse crushing, hydrogen embrittlement pulverizing, middle pulverizing, micro mist be broken can.That is, in the present invention, to the magnetic forming process, importantly mixing these alloys equably, the selecting of selected or mixed method of breaking method do not limited.Even mixing hope is used V-type to mix well machine in inert gas and is implemented.In addition, in order to improve the degree of orientation in the magnetic forming, wish in mixed powder, to add the lubricants such as zinc stearate of 0.01~1 weight %.
Moreover, be in the hydrogen embrittlement crushing process of alloy in principal phase, suction hydrogen is handled to be preferably in the nitrogen atmosphere and is implemented in the temperature more than 100 ℃.From the viewpoint of economy or fail safe, the hydrogen-pressure in the nitrogen atmosphere of this moment is 200 holder~10Kgf/cm preferably
2The dehydrogenation processing procedure, the alloy that generates heat in inhaling the hydrogen process is fully cooled off after, in vacuum, carry out 1 dehydrogenation at normal temperature and handle, preferably keep carrying out more than 30 minutes 2 dehydrogenations at 400 ℃~750 ℃ in Ar gas or in the vacuum again and handle.By carrying out this dehydrogenation processing procedure, improve the later oxidative resistance of process then.From the viewpoint of operating efficiency, also can omit 1 dehydrogenation and handle.
Mixed uniformly micro mist, in atmosphere or inert gas, use the magnetic forming machine to be shaped after, in a vacuum or in the atmosphere of inert gases such as Ar gas, carry out sintering at 1000~1100 ℃.Implementing under the situation that hydrogen embrittlement pulverizes,, before sintering, must remove the hydrogen in the formed body safely for sintering fully, for this reason must be in a vacuum, keep more than 1 hour at 700~900 ℃.If behind sintering, carry out Ageing Treatment in addition, just improve coercive force.Preferred Ageing Treatment condition is in a vacuum or in the inert atmosphere such as Ar gas, keeps carrying out chilling then more than 1 hour at 500~700 ℃.
Abnormal grain even oxygen concentration is controlled to low-level, does not take place yet and grows up in the sintered magnet that obtains in the present invention.Though its reason is not clear, can think near 1040 ℃ in principal phase to be that the rich B that volume exists in the alloy suppresses growing up of crystal grain mutually.In principal phase is that to have the rich B of volume in the alloy also be the feature of invention mutually.
Add a supplementary explanation about the composition among the present invention.
Principal phase of the present invention is that the T composition of alloy must be Fe, and for corrosion resistance or the temperature characterisitic of improving sintered magnet, a part can be used a kind or 2 kinds of replacements of Co, Ni.But the total of replacement amount must be no more than 50 weight % of T composition in the composition behind mixed sintering.If surpass 50 weight %, just can not get high-coercive force, rectangularity also reduces simultaneously.
Principal phase of the present invention is the B composition of alloy, and a part also can be used a kind or 2 kinds of replacements of C, N.But the total of replacement amount must be no more than 30 weight % of B+C+N composition in the composition behind mixed sintering.If surpass 30 weight %, just can not get high-coercive force, rectangularity also reduces simultaneously.
And then, in order to improve coercitive aging temp interdependence, be can add Cu in alloy and the crystal-boundary phase alloy in principal phase.And, be to add a kind among Al, Ti, V, Cr, Mn, Nb, Ta, Mo, W, Ca, Sn, Zr, the Hf in alloy and the crystal-boundary phase alloy or add its several combinations in principal phase in order to improve coercive force.But,, comprise in the composition of total addition behind mixed sintering of these compositions of Cu being no more than 5 weight % in order not reduce the residual magnetic flux density of sintered magnet.
In principal phase of the present invention is in alloy and the crystal-boundary phase alloy, can allow to exist unavoidable impurities on the industrial production such as Y, La, Ce, Sm, C, O, N, Si, Ca.
As mentioned above, according to the present invention, can provide that to allow oxygen concentration for example be the only alloy of raw alloy of the following high performance sintered magnet of 3000ppm as being used to make, and the high performance sintered magnet that crystal grain is difficult to grow up unusually can be manufactured on sintering the time.
Embodiment and comparative example
Below, illustrate in greater detail the present invention according to embodiment.
Embodiment 1
After the principal phase of the composition of table 1 record is alloy melting, utilize the Strip casting method to cast (1450 ℃ of casting temperatures).The diameter of the copper roller that uses in the Strip casting method is 40cm, and the peripheral speed of copper roller is set in 0.98m/s.Resulting alloy is laminar, and its average thickness is 0.35mm.
SEM (scanning electron microscopy) diffraction electronic photo such as Fig. 1 according to this alloy section.From the quantitative analysis of each phase of utilizing EDX (energy dispersion type X type analysis device) and XRD (powder X-ray diffractometry) as can be known, the matrix that presents grey in photo is R mutually
2Fe
14B phase, the sheet that presents black line are α Fe phase mutually.Do not see the rich R of sheet mutually with dendroid α Fe mutually.In XRD, see rich B phase, but in reflected electron image, do not see.Because the color of rich B phase and R in reflected electron image
2Fe
14The color of B phase is very approaching, so both can not be distinguished.
Utilizing image processing apparatus to resolve the diffraction electronic photo image of any 10 sections of this alloy sheet, obtain the zone that forms sheet α Fe phase, is 95 volume %.Only observe R among the remaining 5 volume %
2Fe
14The B phase.
Embodiment 2
With the condition identical with embodiment 1, to utilize the principal phase of the composition of Strip casting method casting table 1 record be alloy, obtaining average thickness is the laminar alloy of 0.30mm.SEM diffraction electronic photo such as Fig. 2 according to this alloy section.From each phase quantitative analysis of utilizing EDX and XRD as can be known, the matrix that presents grey in photo is R mutually
2Fe
14The B phase, what present black line is sheet α Fe phase mutually, most black point-like are dendroid R mutually
2Fe
17Phase, presenting black is dendroid α Fe phase mutually.And, at dendroid R
2Fe
17The white point shape that peripheral part of phase and dendroid α Fe peripheral part mutually occurs be rich R phase mutually.Use and embodiment 1 identical method is carried out the quantitative of the formation zone % of sheet α Fe phase of this alloy and dendroid α Fe formation zone mutually.The results are shown in the table 1.
Embodiment 3
With the condition identical with embodiment 1, to utilize the principal phase of the composition of Strip casting method casting table 1 record be alloy, obtaining average thickness is the laminar alloy of 0.32mm.
Diffraction electronic image, EDX and the XRD that utilizes SEM determines and the principal phase seen is as matrix R mutually
2Fe
14The B phase, sheet α Fe phase, dendroid R
2Fe
17Phase, dendroid α Fe phase.And, at dendroid R
2Fe
17Mutually with dendroid α Fe mutually around, rich R forms many point-like mutually.Have only with XRD and can confirm to form rich B phase, and can not confirm to form rich B phase with other method.
The formation zone of the sheet α Fe phase of this alloy and the formation zone of dendroid α Fe phase are to carry out quantitatively with embodiment 1 identical method.The results are shown in the table 1.
Embodiment 4
With the condition identical with embodiment 1, to utilize the principal phase of the composition of Strip casting method casting table 1 record be alloy.The composition of this alloy is the composition that the part of Fe composition of the alloy of embodiment 1 replaces with Co.The alloy that obtains is laminar, and its average thickness is 0.33mm.
Utilizing SEM diffraction electronic image, EDX and XRD that the section of this alloy is identified forms mutually.Its result, formation be R mutually as the matrix phase
2(FeCo)
14B mutually with sheet α Fe mutually.About rich B phase, have only the XRD of utilization can confirm that rich B forms mutually, and can not confirm to form rich B phase with other method.
The formation zone of the sheet α Fe phase of this alloy and the formation zone of dendroid α Fe phase are to carry out quantitatively with embodiment 1 identical method.The results are shown in the table 1.
Comparative example 1
With the condition identical with embodiment 1, utilize the casting of Strip casting method shown in table 1 record like that than formation R
2Fe
14The many principal phases of R amount of B phase are alloy, and obtaining average thickness is the laminar alloy of 0.30mm.To investigate the formation phase of this alloy with embodiment 1~3 identical method, form the rich R phase of sheet of volume, a spot of dendroid α Fe mutually with rich B mutually.Rich R forms many point-like mutually around this dendroid α Fe phase.Do not see sheet α Fe phase.About rich B phase, have only the XRD of utilization can confirm that rich B forms mutually, and can not confirm to form rich B phase with other method.
The formation zone of the sheet α Fe phase of this alloy and the formation zone of dendroid α Fe phase are to carry out quantitatively with embodiment 1 identical method.The results are shown in the table 1.
Comparative example 2
With the condition identical with embodiment 1, to utilize the principal phase of the Strip casting method casting composition that does not have Dy as shown in table 1 be alloy, the average thickness of resulting laminar alloy is 0.29mm.
To investigate the formation phase of this alloy, be R as the matrix phase with embodiment 1~3 identical method
2Fe
14The B phase, sheet α Fe phase, dendroid α Fe mutually with rich B mutually.And rich R forms many point-like mutually around dendroid α Fe phase.About rich B phase, utilize XRD to confirm that rich B forms mutually, and with the rich B phase of other method formation unconfirmed.
The formation zone of the sheet α Fe phase of this alloy and the formation zone of dendroid α Fe phase are to carry out quantitatively with embodiment 1 identical method.The results are shown in the table 1.
Comparative example 3
With the condition identical with embodiment 1, to utilize the Strip casting method casting principal phase that does not have Dy as shown in table 1 be alloy, obtaining average thickness is the laminar alloy of 0.33mm.
To investigate the formation phase of this alloy, be R as the matrix phase with embodiment 1~3 identical method
2Fe
14The B phase, sheet α Fe phase, dendroid α Fe phase.And rich R forms many point-like mutually around dendroid α Fe phase.
The formation zone of the sheet α Fe phase of this alloy and the formation zone of dendroid α Fe phase are to carry out quantitatively with embodiment 1 identical method.The results are shown in the table 1.
Comparative example 4
With the condition identical with embodiment 1, to utilize the principal phase of the Strip casting method casting Dy that contains volume as shown in table 1 be alloy, obtaining average thickness is the laminar alloy of 0.31mm.
To investigate the formation phase of this alloy, be R as the matrix phase with embodiment 1~3 identical method
2Fe
14The B phase, sheet α Fe phase, dendroid R
2Fe
17Phase, dendroid α Fe phase.And, at dendroid R
2Fe
17Form many point-like mutually with dendroid α Fe rich R on every side mutually mutually.About rich B phase, utilize XRD to confirm that rich B forms mutually, and with the rich B phase of other method formation unconfirmed.
The formation zone of the sheet α Fe phase of this alloy and the formation zone of dendroid α Fe phase are to carry out quantitatively with embodiment 1 identical method.The results are shown in the table 1.
Comparative example 5
With the condition identical with embodiment 1, to utilize the Strip casting method casting many principal phases of B amount as shown in table 1 be alloy, obtaining average thickness is the laminar alloy of 0.32mm.
To investigate the formation phase of this alloy, be R as the matrix phase with embodiment 1~3 identical method
2Fe
14The B phase, sheet α Fe phase, dendroid R
2Fe
17Phase, dendroid α Fe phase.And, at dendroid R
2Fe
17Form many point-like mutually with dendroid α Fe rich R on every side mutually mutually.About rich B phase, utilize XRD to confirm to form a large amount of rich B phases than embodiment 1~3.
The formation zone of the sheet α Fe phase of this alloy and the formation zone of dendroid α Fe phase are to carry out quantitatively with embodiment 1 identical method.The results are shown in the table 1.
Table 1 principal phase is composition, thickness and the tissue of alloy
| Nd+Pr+Dy atom % | Nd atom % | Pr atom % | Dy atom % | B atom % | Co atom % | Fe atom % | The thickness mm of alloy | The formation zone volume % of sheet α Fe | The formation zone volume % of dendroid α Fe | Phase (zero symbol: confirmed phase) that forms |
R
2T
14The B phase
| Sheet α Fe | Dendroid α Fe | Dendroid R
2T
14The B phase
| The rich R phase of point-like | Rich B phase | The rich B phase of sheet |
Embodiment 1 | 11.67 | 8.63 | 0.01 | 3.03 | 7.05 | 0 | 81.28 | 0.35 | 95 | 0 | ○ | ○ | | | | ○ | |
Embodiment 2 | 11.76 | 9.04 | 0.01 | 2.71 | 5.93 | 0 | 82.31 | 0.30 | 72 | 2 | ○ | ○ | ○ | ○ | ○ | | |
Embodiment 3 | 10.42 | 8.24 | 0.01 | 2.17 | 7.90 | 0 | 81.68 | 0.32 | 14 | 9 | ○ | ○ | ○ | ○ | ○ | ○ | |
Embodiment 4 | 11.67 | 8.64 | 0.01 | 3.02 | 7.05 | 0.54 | 80.74 | 0.33 | 94 | 0 | ○ | ○ | | | | ○ | |
Comparative example 1 | 12.44 | 12.43 | 0.01 | 0 | 7.07 | 0 | 80.49 | 0.30 | 0 | 1 | ○ | | ○ | | ○ | ○ | ○ |
Comparative example 2 | 11.69 | 11.67 | 0.02 | 0 | 7.00 | 0 | 81.31 | 0.29 | 71 | 22 | ○ | ○ | ○ | | ○ | ○ | |
Comparative example 3 | 9.92 | 9.90 | 0.01 | 0 | 5.03 | 0 | 85.05 | 0.33 | 8 | 88 | ○ | ○ | ○ | | ○ | | |
Comparative example 4 | 11.77 | 5.32 | 0.01 | 6.44 | 7.13 | 0 | 81.10 | 0.31 | 3 | 0 | ○ | ○ | ○ | ○ | ○ | ○ | |
Comparative example 5 | 11.58 | 8.59 | 0.01 | 2.98 | 9.00 | 0 | 79.42 | 0.32 | 98 | 0 | ○ | ○ | ○ | ○ | ○ | ○ | |
Embodiment 5
Use the crystal-boundary phase alloy " R alloy 1 " of copper casting mold casting table 2 record, its thickness is 5mm, utilizes jaw crusher to be crushed to below the 5mm.Utilize SEM diffraction electronic image and EDX to observe the section of alloy, do not see α Fe phase.
Then, be that the principal phase that 83: 17 cooperation is crushed to the following embodiment 1 of 5mm is alloy and R alloy 1 with weight ratio, so that almost there is not rich B phase in the composition after sintered magnetization.In N
2After in V-type is mixed well device, this complex evenly being mixed in the gas, carry out hydrogen embrittlement and pulverize.The dehydrogenation treatment conditions are to keep 1 hour at 500 ℃ in a vacuum.
At N
2Use Blang's formula pulverizing mill that the mixed powder that obtains is crushed to below the 0.5mm in the gas.After in this mixed powder, cooperating the zinc stearate of 0.05 weight % equably, at N
2Use the injecting type pulverizing mill to pulverize in the gas.The particle mean size of the admixed finepowder that obtains is 3.4 μ m (FSSS).
This admixed finepowder forms in magnetic field.
This press-powder formed body is put into vacuum furnace, kept 1 hour at 800 ℃, remove the hydrogen in the press-powder formed body fully after, keep carrying out in 3 hours sintering at 1060 ℃.After this, 560 ℃ keep carrying out in 1 hour timeliness in a vacuum, follow chilling.The magnetic of the resulting sintered body of record in table 4.
In addition, with the section of polarized light microscope observing sintered body, the size of crystal grain is 10~15 μ m, does not see the crystal grain of growing up unusually.
Embodiment 6
To make the crystal-boundary phase alloy " R alloy 2 " of table 2 record, utilize jaw formula pulverizing mill to be crushed to below the 5mm with embodiment 5 identical methods.Utilize SEM diffraction electronic image and EDX to observe the section of alloy, do not see α Fe phase.
With the principal phase that is modulated into embodiment 1 with embodiment 5 identical methods is the admixed finepowder of alloy and R alloy 2.Mixing ratio is 83: 17 by weight so that in the composition after sintered magnetization the total of Nd, Pr, Dy form and embodiment 5 much at one, and almost do not have rich B phase.The particle mean size of the admixed finepowder that obtains is 3.3 μ m (FSSS).After this,, carry out sintering and timeliness, make sintered magnet in magnetic field, to be shaped with embodiment 5 identical methods.But sintering temperature is 1060 and 1100 ℃.
The magnetic of resulting sintered body is recorded in the table 4.In addition, with the section of polarized light microscope observing sintered body, are 10~15 μ m in the grain size of the sintered magnet of 1060 ℃ of sintering, be 15~20 μ m in the grain size of the sintered magnet of 1100 ℃ of sintering.Which kind of sintered magnet is not all seen the crystal grain of growing up unusually.
Embodiment 7
Using the principal phase of embodiment 4 is alloy and R alloy 2, to be modulated into admixed finepowder with embodiment 5 identical methods.。Mixing ratio is 83: 17 by weight so that in the composition after sintered magnetization the total of Nd, Pr, Dy form and embodiment 6 much at one, and almost do not have rich B phase.The particle mean size of the admixed finepowder that obtains is 3.4 μ m (FSSS).Use this admixed finepowder,, carry out sintering and timeliness, make sintered magnet in magnetic field, to be shaped with embodiment 5 identical methods.But sintering temperature is 1060 and 1100 ℃, and the retention time separately is 3 hours.
The magnetic of resulting sintered body is recorded in the table 4.
In addition, with the section of polarized light microscope observing sintered body, are 10~15 μ m in the grain size of the sintered magnet of 1060 ℃ of sintering, be 15~20 μ m in the grain size of the sintered magnet of 1100 ℃ of sintering.All do not see the crystal grain of growing up unusually.
Embodiment 8
To make the crystal-boundary phase alloy " R alloy 3 " of table 2 record, use jaw formula pulverizing mill to be crushed to below the 5mm with embodiment 5 identical methods.Utilize SEM diffraction electronic image and EDX to observe the section of this alloy, do not see α Fe phase.
Using the principal phase of embodiment 1 is alloy, R alloy 2 and R alloy 3, to be modulated into admixed finepowder with embodiment 5 identical methods.Mixing ratio is 80: 15: 5 by weight, so that almost there is not rich B phase in the composition after sintered magnetization.The particle mean size of resulting admixed finepowder is 3.4 μ m (FSSS).
Use this admixed finepowder,, carry out sintering and timeliness, make sintered magnet in magnetic field, to be shaped with embodiment 5 identical methods.But sintering temperature is 1060 and 1100 ℃, and the retention time separately is 3 hours.
In addition, with the section of polarized light microscope observing sintered body, are 10~15 μ m in the grain size of the sintered magnet of 1060 ℃ of sintering, be 15~20 μ m in the grain size of the sintered magnet of 1100 ℃ of sintering.All do not see the crystal grain of growing up unusually.
Comparative example 6
Such as table 3 record, make the cooperation raw material that becomes the composition identical, with the condition identical, utilize Strip casting method (alloyage) to obtain the laminar alloy of average thickness 0.35mm with embodiment 1 with the mixed powder of embodiment 6.
Utilize SEM diffraction electronic image to observe the section of this alloy.Its result is the R of matrix phase except formation
2Fe
14Outside the B phase, form the rich R phase of many sheets.Do not see dendroid α Fe phase.
Use and this alloy is made micro mist with embodiment 5 identical methods.But the suction hydrogen process in hydrogen embrittlement is pulverized is only implemented at normal temperature.The particle mean size of resulting admixed finepowder is 3.4 μ m (FSSS).Use this micro mist,, carry out sintering and timeliness, make sintered magnet in magnetic field, to be shaped with embodiment 5 identical methods.But sintering temperature is 1060 and 1100 ℃, and the retention time separately is 3 hours.
The magnetic of resulting sintered body is recorded in the table 4.The magnetic of 1100 ℃ of sintered magnets reduces than the magnetic of 1060 ℃ of sintered magnets.And, in the demagnetization curve of 1100 ℃ of sintered magnets, bottleneck being arranged, rectangularity is also poor.
In addition, with the section of polarized light microscope observing sintered body, are 15~20 μ m in the grain size of the sintered magnet of 1060 ℃ of sintering, do not see the crystal grain of growing up unusually.And at the sintered magnet of 1100 ℃ of sintering, even the sintered magnet section is carried out the coarse grain that many about 0.1~0.5mm are also observed in visualization.
Comparative example 7
Using the principal phase of comparative example 4 is alloy and R alloy 2, to be modulated into admixed finepowder with embodiment 5 identical methods.Mixing ratio is 83: 17 by weight, so that almost there is not the B phase in the composition after sintered magnetization.The particle mean size of resulting admixed finepowder is 3.3 μ m (FSSS).
Use this admixed finepowder,, carry out sintering and timeliness, make sintered magnet in magnetic field, to be shaped with embodiment 5 identical methods.
The magnetic of resulting sintered body is recorded in the table 4.Except the Dy composition, if and the sintered magnet of the very approximate embodiment 8 of composition after the magnetization compares, Dy is too much in this sintered magnet, and therefore intrinsic coercive force (iHc) is very big, and remanent magnetization (Br) is reduced to 1.1kG, and maximum energy product (BH) max is reduced to 9.8MGOe.
In addition, with the section of polarized light microscope observing sintered body, grain size is 10~15 μ m, does not see the crystal grain of growing up unusually.
Comparative example 8
Using the principal phase of comparative example 5 is alloy and R alloy 2, to modulate admixed finepowder with embodiment 5 identical methods.Mixing ratio is 83: 17 by weight so that in the composition after sintered magnetization the total of Nd, Pr, Dy form and embodiment 6 much at one.The particle mean size of resulting admixed finepowder is 3.4 μ m (FSSS).
Use this admixed finepowder,, carry out sintering and timeliness, make sintered magnet in magnetic field, to be shaped with embodiment 5 identical methods.
The magnetic of resulting sintered body is recorded in the table 4.Except the B composition, and if the sintered magnet of the very approximate embodiment 6 of composition after the magnetization compare, B is too much in this sintered magnet, so remanent magnetization (Br) is reduced to 0.6kG, maximum energy product (BH) max is reduced to 4.3MGOe.
With the section of polarized light microscope observing sintered body, the size of crystal grain is 10~15 μ m, does not see the crystal grain of growing up unusually.
Comparative example 9
Using the principal phase of comparative example 2 is alloy and R alloy 2, to be modulated into admixed finepowder with embodiment 5 identical methods.Mixing ratio is 83: 17 by weight, so that almost there is not rich B phase in the composition after sintered magnetization.The particle mean size of resulting admixed finepowder is 3.4 μ m (FSSS).
Use this admixed finepowder,, carry out sintering and timeliness, make sintered magnet in magnetic field, to be shaped with embodiment 5 identical methods.
The magnetic of resulting sintered magnet is recorded in the table 4.The rectangularity of demagnetization curve is on duty mutually.Analyze the Fe composition of this sintered magnet, reduce by 0.4 weight % than the Fe composition that uses Blang's formula pulverizing mill crushed mixed powder.On the other hand, analyze the Fe composition of residual powder in the injecting type grinding mechanism, increase by 1.5 weight % than the Fe composition that uses Blang's formula pulverizing mill crushed mixed powder.From these susceptible of proofs, if in principal phase is to form dendroid α Fe phase in the alloy in large quantities, with injecting type grind just be difficult to this α Fe phase micro mist broken, therefore remain in the injecting type pulverizing mill, the original powder constituent of ratio of components that becomes powder is shifted to the composition deviation of rich R side and powder and the reason that comprises α Fe in powder, and the magnetic of magnet also reduces.
The composition of table 2 crystal-boundary phase alloy
| Nd+Pr+Dy atom % | ND atom % | Pr atom % | Dy atom % | B atom % | Co atom % | Cu atom % | Fe atom % |
R alloy 1 | 28.57 | 25.59 | 0.02 | 2.96 | 0 | 0 | 0 | 71.43 |
R alloy 2 | 28.6 | 25.68 | 0.02 | 2.96 | 0 | 4.28 | 0.35 | 66.71 |
R alloy 3 | 27.26 | 24.41 | 0.02 | 2.83 | 5.76 | 0 | 0 | 66.98 |
R alloy 4 | 14.52 | 11.64 | 0.02 | 2.86 | 0 | 4.3 | 0.35 | 80.83 |
Table 3-alloyage the composition and thickness of raw alloy
| Form | The thickness mm of alloy |
Nd+Pr+Dy atom % | ND atom % | Pr atom % | Dy atom % | B atom % | Co atom % | Cu atom % | Fe atom % |
Comparative example 6 | 14.18 | 11.14 | 0.01 | 3.03 | 6.18 | 0.58 | 0.05 | 79.01 | 0.35 |
The magnetic of table 4 sintered magnet and approximate grain size
| Magnetic | Crystal grain (μ m) |
Sintering temperature ℃ | Sintered density g/cm
3 | Br KG | iHC kOe | (BH)max MGOe |
Embodiment 5 | 1060 | 7.52 | 12.0 | 27.8 | 35.5 | 10~15 |
Embodiment 6 | 1060 | 7.51 | 11.8 | 27.6 | 34.4 | 15~20 |
Embodiment 6 | 1100 | 7.57 | 12.1 | 26.5 | 35.0 | 10~15 |
Embodiment 7 | 1060 | 7.52 | 12.0 | 27.2 | 34.2 | 15~20 |
Embodiment 7 | 1100 | 7.57 | 12.2 | 26.3 | 35.1 | 10~15 |
Embodiment 8 | 1060 | 7.52 | 11.8 | 26.7 | 33.6 | 15~20 |
Embodiment 8 | 1100 | 7.58 | 12.0 | 25.8 | 34.5 | 15~20 |
Comparative example 6 | 1060 | 7.51 | 12.0 | 27.2 | 35.1 | The coarse grain of many φ 0.1~φ 0.5 mm |
Comparative example 6 | 1100 | 7.58 | 11.7 | 23.7 | 29.8 | 15~20 |
Comparative example 7 | 1060 | 7.52 | 10.1 | 30 | 24.4 | 15~20 |
Comparative example 8 | 1060 | 7.52 | 11.2 | 27.0 | 30.1 | 15~20 |
Comparative example 9 | 1060 | 7.52 | 12.3 | 8.9 | 16.4 | 10~15 |
Comparative example 10
To cast the crystal-boundary phase alloy " R alloy 4 " that tables 2 are put down in writing with embodiment 2 identical conditions.
Utilize SEM diffraction electronic image to observe the section of this alloy and carry out EDX and analyze, find out the α Fe phase that forms volume.Select any 10 positions at the section of this alloy, production reflection electronic photo, the generation zone of using the quantitative formed α Fe phase of image processing apparatus is 38 volume %.
Embodiment 9
In atmosphere, be placed on the press-powder formed body after being shaped in the magnetic field of making among the embodiment 6, measure the variation of oxygen concentration.The results are shown in the table 5.
Comparative example 11
Using the principal phase of comparative example 1 is alloy and R alloy 2, to make admixed finepowder with embodiment 5 identical methods.Mixing ratio is 83: 17 by weight, so that almost there is not rich B phase in the composition after sintered magnetization.The particle mean size of resulting micro mist is 3.4 μ m (FSSS).
Use this admixed finepowder, be shaped to carry out the magnetic field press-powder with embodiment 5 identical methods.Measure the variation of the oxygen concentration of this press-powder formed body.The results are shown in the table 5.Compare as can be known the easy oxidation of press-powder formed body with embodiment 9.
Comparative example 12
In atmosphere, be placed on the press-powder formed body after being shaped in the magnetic field of making among the embodiment 6, measure the variation of oxygen concentration.The results are shown in the table 5.Compare as can be known the easy oxidation of formed body with embodiment 9.
Standing time and the oxygen concentration of formed body behind table 5 magnetic forming in atmosphere
| Standing time in the atmosphere |
0 hour | 6 hours |
Embodiment 9 | 3000ppm | 3800ppm |
Comparative example 11 | 3000ppm | 6900ppm |
Comparative example 12 | 3000ppm | 6100ppm |