CN105702402A - Rare-earth permanent magnet powder, preparation method thereof, bonded permanent magnet and device - Google Patents

Abstract

The invention discloses rear-earth permanent magnet powder, a preparation method thereof, a bonded permanent magnet and a device. Based on total weight by 100 parts, the general formula of the rear-earth permanent magnet powder is R<a>AlphaR<b>BeltaFe100-Alpha-Belta-Theta-Phi-DeltaMThetaBPhiFDelta, R<a> is at least one element of Pr and Nd, Alpha is more than or equal to 18 but less than or equal to 27, R<b> is at least one element of Tb and Dy, Belta is more than or equal to 0.1 but less than or equal to 3, M is one or two elements of Co, Zr, Nb, Ti, Cr, Si and Al, Theta is more than or equal to 0 but less than or equal to 5, B is boron, Phi is more than or equal to 0.8 but less than or equal to 1.5, F is fluorine, Delta is more than or equal to 0.05 but less than or equal to 0.1, a main phase comprises R<a>2Fe14B and Alpha-Fe, R<b> is arranged between the R<a>2Fe14B and the Alpha-Fe in a (R<a>R<b>)2Fe14B phase, and the concentration of the R<b> at the R<a>2Fe14B grain boundary is higher than that at the interior of the R<a>2Fe14B. The rare-earth permanent magnet powder is high in residual magnetic flux and high in coercivity.

Description

Rare earth permanent magnet powder, its preparation method, bonded permanent magnet and device

Technical field

The present invention relates to permanent magnetism pink collar territory, in particular to a kind of rare earth permanent magnet powder, its preparation method, bonded permanent magnet and device。

Background technology

In recent years, people work out nanocrystalline composite permanent-magnet material, and it is the one of nano composite material。Its basic physical thought is: utilize soft magnetism phase (such as α-Fe) high saturation magnetization and Hard Magnetic phase (such as Nd₂Fe₁₄B) there is high coercivity and high magnetocrystalline anisotropy, by realizing spin-exchange-coupled within the scope of nanoscale, thus obtaining the magnetic powder of high remanent magnetism, high-coercive force。But in actual fabrication process, it is difficult to reach the requirements such as the crystallite dimension nanometer required by diphasic magnet theoretical model, distribution, orientation。Due to the introducing of soft magnetism phase α-Fe, although the remanent magnetism of magnetic powder obtains certain raising, but coercivity occurs in that and significantly declines, and thus affects and limits a nanometer two-phase magnetic powder application in higher temperature field。

In addition, research worker is also done a lot of work in element doping and preparation link, in element doping, magnetic particle capability is usually improved mainly through adding high-melting-point unit, but how to introduce precipitated phase, in the different phase of preparation, effect that the element of doping each serves as and on the impact of properties of product how but and indefinite。And in preparation link, it is concentrated mainly on crystallization process, as by high fast annealing, high pressure annealing, laser annealing etc., although these preparation methoies all obtain higher nanometer of two-phase magnetic powder of remanent magnetism at laboratory, but the magnetic powder coercivity value of preparation is all on the low side, and these method difficulty of preparation technology are high, condition is harsh, is not suitable for promoting。

Therefore, it is still necessary to the preparation technology of of the prior art nanometer of two-phase magnetic powder is improved, to provide the magnetic powder of a kind of high-coercive force, high remanent magnetism。

Summary of the invention

It is desirable to provide a kind of rare earth permanent magnet powder, its preparation method, bonded permanent magnet and device, high-coercive force and the defect of high remanent magnetism can not be had concurrently solving a nanometer two-phase magnetic powder in prior art。

To achieve these goals, according to an aspect of the invention, it is provided a kind of rare earth permanent magnet powder, in gross mass 100 parts, the formula of rare earth permanent magnet powder isWherein, α, β, θ,Mass parts, R is represented with δ^aFor at least one element in Pr, Nd, 18≤α≤27；R^bFor at least one element in Tb, Dy, 0.1≤β≤3；M is one or both elements in Co, Zr, Nb, Ti, Cr, Si, Al, 0≤θ≤5；B is boron element,F is fluorine element, 0.05≤δ≤0.1, and the principal phase of rare earth permanent magnet powder is by R^a ₂Fe₁₄B and α-Fe phase composition；R in rare earth permanent magnet powder^bWith (R^aR^b)₂Fe₁₄B phase is distributed in R^a ₂Fe₁₄Between B and α-Fe is biphase。

Further, 20≤α≤25。

Further, R^bFor Dy, and 0.3≤β≤2。

Further, when M is element nb and Ti, 0.3≤θ≤2。

Further, R^bAt R^a ₂Fe₁₄The concentration of B grain boundary is higher than it at R^a ₂Fe₁₄B intra-die。

Further, rare earth permanent magnet powder principal phase R^a ₂Fe₁₄The crystallite dimension of B is 10～50nm, it is preferred to 20～40nm；The crystallite dimension of α-Fe is 10～30nm。

According to another aspect of the present invention, it is provided that the preparation method of a kind of rare earth permanent magnet powder, this preparation method comprises the following steps: according toProportioning prepareMagnetic powder；WillMagnetic powder and R^bF₃Powder mixes, and obtains mixture；Mixture is carried out heat treatment, obtainsRare earth permanent magnet powder。

Further,Magnetic powder particle is of a size of 60～200 μm, it is preferred to 80～150 μm。

Further,Magnetic powder and R^bF₃Powder mixes according to the ratio of mass ratio 100:0.1～5, obtains mixture；Preferred mass is than for 100:0.5～2。

Further, R^bF₃The particle size of powder is 0.01～0.2 μm；It is preferably 0.03～0.1 μm。

Further, heat treated temperature is 400～900 DEG C, and the time is 1～30min；Preferred heat treated temperature is 550～800 DEG C, and the time is 5～15min。

Further, the heating rate in heat treatment process is 10～500 DEG C/min；Preferred heating rate is 50～200 DEG C/min。

Further, after heat treatment terminates, obtainBefore rare earth permanent magnet powder, also include the step that the mixture after heat treatment is cooled down according to the cooldown rate of 200～1000 DEG C/min；Preferred cooldown rate is 300～600 DEG C/min。

Further, according toProportioning prepareThe step of magnetic powder carries out under an argon atmosphere, it is preferable that the flow of passed into argon is 0.1～10m³/h。

Further, according toProportioning prepareThe step of magnetic powder includes: will be according toThe mixed mixed material of proportioning is put in crucible and is heated, and obtains alloy molten solution；By alloy molten solution by being arranged on crucible bottom and coupled nozzle is ejected into the water-cooled running roller of rotation and cools down, obtain cooled alloy band: crushed by cooled alloy band, obtainMagnetic powder。

Further, the aperture of nozzle is 0.4～2mm, and thickness is 5～10mm。

Further, it is preferable to the rotating speed of water-cooled running roller is 15～30m/s。

Further, the roughness of water-cooled running roller is 0.1～2 μm。

According to a further aspect in the invention, it is provided that a kind of bonded permanent magnet, any of the above-described kind of rare earth permanent magnet powder and binding agent is utilized to be prepared from。

In accordance with a further aspect of the present invention, a kind of device is additionally provided, including preceding claim bonded permanent magnet。

Application technical scheme, the present invention by introducing Tb, Dy as doped chemical R in nanometer two-phase magnetic powder^b, and optimize R^bProportioning between element and other elements makes to be formed with R^a ₂Fe₁₄B and α-Fe is the rare earth permanent magnet powder of principal phase structure mutually, and R^bWith (R^aR^b)₂Fe₁₄B phase is distributed in R^a ₂Fe₁₄Between B and α-Fe is biphase, and element R^bAt R^a ₂Fe₁₄The concentration of B grain boundary is higher than it at R^a ₂Fe₁₄B intra-die。Due to (R^aR^b)₂Fe₁₄B phase has high HCJ and an anisotropy field, and nanocrystalline (R^aR^b)₂Fe₁₄B phase and R^a ₂Fe₁₄B phase is the same, also can produce exchange-coupling interaction mutually with α-Fe, thus make nanometer two-phase magnetic powder finally given both have the high remanent magnetism of α-Fe phase, have again (R^aR^b)₂Fe₁₄B phase and R^a ₂Fe₁₄The high-coercive force of B phase。And by the Technology for Heating Processing of the present invention, obtain high remanent magnetism, high-coercive force magnetic powder。

Accompanying drawing explanation

The Figure of description constituting the part of the application is used for providing a further understanding of the present invention, and the schematic description and description of the present invention is used for explaining the present invention, is not intended that inappropriate limitation of the present invention。In the accompanying drawings:

Fig. 1 is the XRD diffraction pattern of the rare earth permanent magnet powder in embodiments of the invention 5；And

Fig. 2 is the transmission electron microscope picture of the rare earth permanent magnet powder in embodiments of the invention 5。

Detailed description of the invention

It should be noted that when not conflicting, the embodiment in the application and the feature in embodiment can be mutually combined。Describe the present invention below with reference to the accompanying drawings and in conjunction with the embodiments in detail。

It is previously mentioned as background section, prior art is difficult to prepare the defect of nanometer two-phase magnetic powder of high-coercive force, high remanent magnetism, in order to improve drawbacks described above, in a kind of typical embodiment of the present invention, provide a kind of rare earth permanent magnet powder, in gross mass 100 parts, the formula of rare earth permanent magnet powder isWherein, R^aFor at least one element in Pr, Nd, 18≤α≤27；R^bFor at least one element in Tb, Dy, 0.1≤β≤3；M is one or both elements in Co, Zr, Nb, Ti, Cr, Si, Al, 0≤θ≤5；B is element boron, 0.8≤φ≤1.5, and F is element F, 0.05≤δ≤0.1；The principal phase of rare earth permanent magnet powder is by R^a ₂Fe₁₄B and α-Fe phase composition；R in rare earth permanent magnet powder^bWith (R^aR^b)₂Fe₁₄B phase is distributed in R^a ₂Fe₁₄Between B and α-Fe is biphase。

The above-mentioned rare earth permanent magnet powder of the present invention, by selecting suitable doped chemical R^bAnd optimize R^bProportioning between element and other elements makes to be formed with R^a ₂Fe₁₄B and α-Fe is the rare earth permanent magnet powder of principal phase structure mutually, and R^bWith (R^aR^b)₂Fe₁₄B phase is distributed in R^a ₂Fe₁₄Between B and α-Fe is biphase, and element R^bAt R^a ₂Fe₁₄The concentration of B grain boundary is higher than it at R^a ₂Fe₁₄B intra-die。Due to (R^aR^b)₂Fe₁₄B phase has high HCJ and an anisotropy field, and nanocrystalline (R^aR^b)₂Fe₁₄B phase and R^a ₂Fe₁₄B phase is the same, also can produce exchange-coupling interaction mutually with α-Fe, thus make nanometer two-phase magnetic powder finally given both have the high remanent magnetism of α-Fe phase, have again (R^aR^b)₂Fe₁₄B phase and R^a ₂Fe₁₄The high-coercive force of B phase。

R in the above-mentioned rare earth permanent magnet powder of the present invention^aIt is chosen as at least one element in Pr, Nd, is because Pr or the Nd R formed^a ₂Fe₁₄B phase has higher anisotropy field and saturation magnetization。If what select 18≤α≤27 reason is that α is lower than 18, Hard Magnetic phase R^a ₂Fe₁₄The ratio regular meeting of B phase is relatively fewer, and owing to lacking Hard Magnetic phase, bigger decline occurs in the value directly resulting in coercivity and remanent magnetism；And α is higher than 27, will result in the decline of α-Fe soft magnetism Phase Proportion, additionally will also result in increasing of the waste of resource and non-magnetic phase, the decline to the overall performance of magnet。

And work as R^aIn within the scope of 20≤α≤25wt%, Hard Magnetic phase R in the magnetic powder of preparation^a ₂Fe₁₄B phase is optimal proportion with soft magnetism α-Fe mutually, and within the scope of this, R^a ₂Fe₁₄The Grain-Boundary Phase of B phase is also relatively many, is conducive to (the R of the present invention^aR^b)₂Fe₁₄B is distributed in grain boundary place, makes the performance of prepared magnetic powder preferably。

In the above-mentioned rare earth permanent magnet powder of the present invention, R^bThe selection of element is due to Tb₂Fe₁₄B and Dy₂Fe₁₄The anisotropy field of B is Nd respectively₂Fe₁₄3 times of B and 2 times, therefore, R^bAt least one element being chosen as in Tb, Dy makes the (R of the present invention^aR^b)₂Fe₁₄B phase has high HCJ and an anisotropy field, and nanocrystalline (R^aR^b)₂Fe₁₄B phase and R^a ₂Fe₁₄B phase is the same, also can produce exchange-coupling interaction mutually with α-Fe, is conducive to improving the coercivity of rare earth permanent magnet powder。Consider that metal Tb is expensive, and as strategy metal, due to cost considerations, in the present invention, it is preferred to R^bElement is Dy。

In the above-mentioned rare earth permanent magnet powder of the present invention, by R^bThe content range of element controls in 0.1≤β≤3, is owing to such as β is lower than 0.1, nanocrystalline (R^aR^b)₂Fe₁₄The ratio regular meeting of B phase is considerably less, so that coercitive raising is inconspicuous。And β is higher than 3, will result in (R^aR^b)₂Fe₁₄B Phase Proportion is superfluous, (R^aR^b)₂Fe₁₄B phase is at R^a ₂Fe₁₄B intra-die ratio will raise, and (R^aR^b)₂Fe₁₄The saturation magnetization of B is not as good as R^a ₂Fe₁₄The half of B, can affect the remanent magnetism of magnetic powder, and will also result in the waste of resource。And R^bThe content range of element controls in the scope of 0.3≤β≤2, makes Hard Magnetic phase (R in prepared magnetic powder^aR^b)₂Fe₁₄B、R^a ₂Fe₁₄More preferably, the performance of its magnetic powder prepared is also for more preferably for B phase and soft magnetism α-Fe Phase Proportion。

In the above-mentioned rare earth permanent magnet powder of the present invention, M is one or both elements in Co, Zr, Nb, Ti, Cr, Si, Al。Co, Zr, Nb, Ti, these several elements can both substitute soft or hard biphase in Fe atom, and the interaction between atom can be strengthened so that coercivity, remanent magnetism strengthen simultaneously。It can also enough, growing up of crystal grain is played greatly inhibitory action, thus optimizing tissue micro structure, promote biphase between exchange-coupling interaction, improve magnetic property。And the introducing of Al, Si, Cr can increase principal phase uniaxial anisotropy, reduce disadvantageous in-plane anisotropy so that coercivity significantly improves。The present invention is all had positive effect by choosing of these elements。In above-mentioned rare earth permanent magnet powder, the content of M element reason in the scope of 0≤θ≤5 is: when θ is higher than 5, it will introduce too much non-magnetic phase, cause the decline of magnetic particle capability。

In a kind of preferred embodiment of the present invention, above-mentioned element M is element nb and Ti。Nb can play the effect of crystal grain thinning, so can make principal phase R prepared by the present invention^a ₂Fe₁₄The crystallite dimension of B is effectively controlled so that magnetic powder coercivity significantly improves, and Ti can suppress some similar Nd in heat treatment process₂Fe₂₃B₃Metastable phase precipitate out so that the present invention can complete at a lower temperature, and changes the magnetic powder precipitation mode in heat treatment process α-Fe phase so that R^a ₂Fe₁₄The crystal grain of B phase and α-Fe phase is more uniform。The present invention completes (R in relatively low heat treatment temperature^aR^b)₂Fe₁₄B、R^a ₂Fe₁₄B phase, α-Fe phase precipitation extremely important, relatively low temperature ensure that element R^bIt is mainly distributed on grain boundary place, and does not enter intra-die。

When the above-mentioned M element of the present invention is Nb and Ti, the content of element M is 0.3≤θ≤2, within the scope of this, it is possible to make R in the magnetic powder of preparation^a ₂Fe₁₄The crystallite dimension of B phase and α-Fe phase in preferably scope, i.e. principal phase R^a ₂Fe₁₄The crystallite dimension of B is the crystallite dimension of 20～40nm, α-Fe is 10～30nm, and magnetic powder is conducive to and R in this crystallite dimension^bF₃Mixing, this crystallite dimension is more beneficial for R^bReplace R^a ₂Fe₁₄R in B^aPosition, formed high-coercive force (R^aR^b)₂Fe₁₄B phase。

In the above-mentioned rare earth permanent magnet powder of the present invention, element B can form R^a ₂Fe₁₄B and (R^aR^b)₂Fe₁₄B phase, and if content is lower than 0.8 or higher than 1.5, by impact generation R^a ₂Fe₁₄The ratio of B, easily makes the hydraulic performance decline of magnetic powder, and within content range of the present invention, Hard Magnetic phase R^a ₂Fe₁₄The ratio of B and soft magnetism phase α-Fe preferably, is conducive to the raising of magnetic particle capability。

In the above-mentioned rare earth permanent magnet powder of the present invention, element F can form R^bF₃Phase, and R^bF₃It is a kind of stable compound, will not decompose in heat treatment process of the present invention, and R^bF₃Powder is easily prepared, and is conducive to the enforcement of the present invention, it is easy to realize industrialization。And, in heat treated process, element F is mainly distributed on magnetic powder grain boundary place the R with grain boundaries^a2O₃Form R^aFO, R^aFO by anchoring effect, is conducive to improving the coercivity of magnetic powder at crystal boundary。When the content of F element is controlled within 0.05～0.1 scope by the present invention, R^bForm (R^aR^b)₂Fe₁₄Preferably, itself and α-Fe meet and produce stronger exchange-coupling interaction the ratio of B phase。When the content of F is lower than 0.05, affect element R^bForm (R^aR^b)₂Fe₁₄The content of B phase, more than 0.1, Magnetic Properties of Magnetic is unfavorable。

Principal phase R in the above-mentioned rare earth permanent magnet powder of the present invention^a ₂Fe₁₄The crystallite dimension of B controls to reason is that size is lower than 10nm at 10～50nm, and current preparation means is difficult to prepare, it is difficult to realize industrialization；During more than 50nm, it is unfavorable for R^bF₃With R^a ₂Fe₁₄B forms (R^aR^b)₂Fe₁₄B phase。And in the present invention, the crystallite dimension of rare earth permanent magnet powder is preferably 20～40nm, magnetic powder is conducive to and R in this crystallite dimension^bF₃Mixing, is more beneficial for element R^bAt R in heat treatment process^a ₂Fe₁₄The position of B grain boundaries substituted element Ra, forms (the R of high-coercive force^aR^b)₂Fe₁₄B phase。And the crystallite dimension of principal phase α-Fe is lower than 10nm, current preparation means is difficult to prepare, and is equally also difficult to industrialization；During more than 30nm, it is unfavorable for R^a ₂Fe₁₄B、((R^aR^b)₂Fe₁₄B phase and α-Fe form stronger exchange-coupling interaction, do not reach the effect of high-coercive force of the present invention, high remanent magnetism。

And, the above-mentioned rare earth permanent magnet powder of the present invention is because of with α-Fe phase and R^a ₂Fe₁₄B is principal phase, has high remanent magnetism and the (R of α-Fe phase^aR^b)₂Fe₁₄B phase and R^a ₂Fe₁₄The high-coercive force of B phase, nanometer two-phase magnetic powder finally given has high remanent magnetism, high-coercive force。

Under the teachings of the present invention, those skilled in the art have the ability to select suitable mode to prepare above-mentioned rare earth permanent magnet powder, in the preferred embodiment of the present invention, in the another kind of typical embodiment of the present invention, the preparation method of above-mentioned rare earth permanent magnet powder comprises the following steps: according to above-mentioned R^a _αFe_100-α-θ-φM_θB_φProportioning prepare R^a _αFe_100-α-θ-φM_θB_φMagnetic powder；To R^a _αFe_{100- α-θ-φ}M_θB_φMagnetic powder and R^bF₃Powder mixes, and obtains mixture；Mixture is carried out heat treatment, obtains R^a _αR^b _βFe_{100- α-β-θ-φ-δ}M_θB_φF_δRare earth permanent magnet powder。

The above-mentioned preparation method of the present invention is by preparing R by fast quenching with broken according to above-mentioned element proportioning^a _αFe_100-α-θ-φM_θB_φMagnetic powder, and the R that will obtain^a _αFe_100-α-θ-φM_θB_φMagnetic powder and R^bF₃Powder carries out heat treatment again after mixing, thus obtaining the above-mentioned with α-Fe and R of the present invention^a ₂Fe₁₄B is principal phase, and R^bWith (R^aR^b)₂Fe₁₄B phase is distributed in R^a ₂Fe₁₄Between B and α-Fe is biphase。Because of (R^aR^b)₂Fe₁₄B phase has high HCJ and anisotropy field and and R^a ₂Fe₁₄B is the same, it is possible to produce exchange-coupling interaction mutually with α-Fe so that the rare earth permanent magnet powder of the present invention had both had the high remanent magnetism of α-Fe phase, had again (R^aR^b)₂Fe₁₄B phase and R^a ₂Fe₁₄The high-coercive force of B phase。This high remanent magnetism, high-coercive force rare earth permanent magnet powder compare a traditional nanometer two-phase magnetic powder there is higher operating temperature, be applicable to broader application。

Below with reference to the preparation method that preferred implementation further illustrates above-mentioned rare earth permanent magnet powder provided by the present invention。Wherein:

Dispensing and prepare foundry alloy: according to R^a _αFe_100-α-θ-φM_θB_φProportioning carries out dispensing, prepares foundry alloy with mid-frequency melting furnace melting, wherein R^aFor at least one element in Nd, Pr, 18≤α≤27, M is one or both elements in Co, Zr, Nb, Ti, Cr, Si, Al, and content is 0≤θ≤5, and B is element boron, and content is 0.8≤φ≤1.5, and surplus is Fe and inevitable impurity。

Fast quenching and broken: will according to R^a _αFe_100-α-θ-φM_θB_φFoundry alloy prepared by proportioning is put in crucible; then pass through Medium frequency induction foundry alloy is heated; during existing liquation pending; pass into Ar gas to protect, after alloy forms liquation completely, make liquation be ejected into the water-cooled running roller of rotation by nozzle; after aluminium alloy throws away with the running roller rotated; first it is ejected into the copper coin cooling with cooling water, then passes through disintegrating machine and alloy strip is crushed, R after broken^a _αFe_100-α-θ-φM_θB_φThe particle size of magnetic powder is 60～200 μm；

Selecting argon gas atmosphere protection to can ensure that fast quenching process is smoothed out, the oxygen content of prepared magnetic powder is lower than 500ppm, and this will to (R in follow-up heat treatment process^aR^b)₂Fe₁₄B phase is favourable with the exchange-coupling interaction of α-Fe phase。And the argon gas atmosphere preferably flowed, and the flow-control of argon will be passed at 0.1～10m³Within the scope of/h so that the oxygen content of the magnetic powder of preparation is lower than 300ppm, and the coercivity improving magnetic powder is favourable。

In practical operation, the nozzle for spraying molten alloy liquid is generally made up of high-temperature refractory, for instance quartz, BN or Al₂O₃。In the present invention, the preferred BN material of material of nozzle, the diameter of the aperture of nozzle is 0.4～2mm, thickness is 5～10mm, select 0.4～2mm's to reason is that diameter is lower than 0.4mm, current mechanical processing tools is difficult to prepare, during more than 2mm, the amount that the aluminium alloy unit interval contacts with molybdenum wheel is too much, so will not reach desirable cooling effect, can not get the crystallite dimension that the present invention needs, thickness is less than 5mm, the intensity of BN can be impacted, it is unfavorable for the enforcement of the present invention, more than 10mm, the probability of BN aperture clogs in fast quenching process will be strengthened, it is unfavorable for the smooth enforcement of the present invention。

The preferred molybdenum wheel of material of running roller, molybdenum wheel has better heat conductivility, owing to melt spun alloy band needs quickly to be cooled into required grain size, selecting the better molybdenum wheel of heat conductivility to be conducive to obtaining the crystallite dimension that the present invention needs, this crystallite dimension is conducive to improving the coercivity of magnetic powder。What linear velocity chose 15～30m/s reason is that lower than 15m/s, it is blocked up that the crystallite dimension obtained after subsequent heat treatment crosses thick and magnetic powder thickness, it is unfavorable for the follow-up broken particle size reaching application claims, the effect of the present invention will be affected, more than 30m/s, the phase structure of magnetic powder is difficult to control to, it is unfavorable for the enforcement of the present invention, it addition, excessive velocities, the requirement of equipment is also higher, the cost of operation can be increased。

Running roller roughness select 0.1～2 μm reason is that running roller has certain roughness, the one-tenth band rate of alloy strip can be promoted, avoid the grain growth of magnetic powder in fast quenching process simultaneously。It addition, roughness is lower than 0.1 μm, current machining level is difficult to reach, and can increase production cost, during more than 2 μm, becoming unstable, and affecting the granular size of magnetic powder of the present invention, thus affecting the performance of the magnetic powder of follow-up preparation in fast quenching process。

The broken of the present invention is to adopt the crushing mechanism carried in fast quenching equipment to carry out crushing, and controls, at 80～150 μ m, to be conducive to R by the particle size of the broken magnetic powder obtained^a ₂Fe₁₄B phase and R^bF₃Powder Homogeneous phase mixing, so that in follow-up heat treatment process, element R^bCan with (R^aR^b)₂Fe₁₄B phase is distributed in R^a ₂Fe₁₄Between B and α-Fe is biphase, nanometer two-phase magnetic powder of high-coercive force, high remanent magnetism may finally be obtained, if not within the scope of this, the magnetic property of the magnetic powder of the present invention will be affected。

Batch mixing need to ensure R^a _αFe_100-α-θ-φM_θB_φMagnetic powder and R^bF₃Powder is sufficiently mixed, it is advantageous to machinery batch mixer mixing, artificial mixing may be uneven, so will affect the present invention and prepare the performance of magnetic powder。

Heat treatment: by R obtained above^a _αFe_100-α-θ-φM_θB_φMagnetic powder and R^bF₃Powder mixes according to mass ratio 100:0.1～5, obtains mixture, then this mixture is carried out heat treatment, can obtain the above-mentioned rare earth permanent magnet powder of the present invention。

In the present invention, by R^a _αFe_100-α-θ-φM_θB_φMagnetic powder and R^bF₃The mass ratio of powder mixing is chosen as the reason of 100:0.1～5, improve inconspicuous lower than 100:0.1 coercivity, during higher than 100:5, although the coercivity of the magnetic powder of preparation is greatly improved, but remanent magnetism occurs in that decline, is unfavorable for the invention process, the present invention recommends preferred 100:0.5～2, reason is, within the scope of this, is conducive to the coercitive raising of the present invention and remanent magnetism to keep maximum。

R in said mixture^bF₃The particle size of powder is chosen as 0.01～0.2 μm, is because working as R^bF₃When the particle size of powder is lower than 0.01 μm, increase the difficulty of preparation；During more than 0.2 μm, it is unfavorable in follow-up heat treatment process element R^bEnter R^a ₂Fe₁₄B grain boundaries, occupies R^aPosition, forms (R^aR^b)₂Fe₁₄B phase。And more preferably R in the present invention^bF₃The particle size of powder be 0.03～0.1 μm reason is that within the scope of this, be more beneficial in follow-up heat treatment process element R^bEnter R^a ₂Fe₁₄B crystal particle crystal boundary place, occupies R^aPosition, forms (R^aR^b)₂Fe₁₄B phase。

In above-mentioned heat treatment process, the reason that heat treated temperature is 400～900 DEG C is, lower than 400 DEG C, and (R^aR^b)₂Fe₁₄B phase is difficult to be formed, and higher than 900 DEG C, the crystal grain of magnetic powder can become thick, and the coercivity of magnetic powder is unfavorable。And the present invention more preferably heat treated temperature is 550～880 DEG C, in this temperature range, R^bEasily enter R^a ₂Fe₁₄B phase, easily at R^a ₂Fe₁₄B crystal particle crystal boundary place forms (R^aR^b)₂Fe₁₄B phase。Heat treatment time selects when reason is that heat treatment time lower than 1min of 1～30min, R^bIt is difficult to enter R^a ₂Fe₁₄B phase forms (R at grain boundaries^aR^b)₂Fe₁₄B phase, and during higher than 30min, will result in R^a ₂Fe₁₄B、(R^aR^b)₂Fe₁₄B phase, excessively the growing up of α-Fe phase, and R^bR can be entered^a ₂Fe₁₄B intra-die, rather than it is distributed in grain boundaries, after entering inside, cause the remanent magnetism of magnetic powder to decline。More preferably heat treatment time is 5～15min, in this temperature range, and R^bEasily enter R^a ₂Fe₁₄B phase forms (R at grain boundaries^aR^b)₂Fe₁₄B phase and R^a ₂Fe₁₄B、(R^aR^b)₂Fe₁₄B phase, α-Fe phase crystallite dimension also in the scope of application claims, the coercivity of the magnetic powder so obtained and remanent magnetism will easily reach more preferably。

In the above-mentioned preparation method of the present invention, heat treated heating rate is 10～500 DEG C/min。If owing to heating rate is lower than 10 DEG C/min, R can be made^a _αFe_100-α-θ-φM_θB_φThe crystallite dimension of magnetic powder is grown up, and is unfavorable for that improve coercivity produces exchange-coupling interaction mutually with α-Fe, and higher than 500 DEG C/min, by the input of the equipment of increasing, is unfavorable for realizing industrialization。The present invention more preferably heating rate is 50～200 DEG C/min, within the scope of this, and magnetic powder R^a ₂Fe₁₄B、(R^aR^b)₂Fe₁₄B phase, α-Fe phase crystallite dimension will be effectively controlled, be conducive to the performance of magnetic powder of the present invention。

In the above-mentioned preparation method of the present invention, after heat treatment terminates, obtain described R^a _αR^b _βFe_{100-α-β-θ-φ-δ}M_θB_φF_δBefore rare earth permanent magnet powder, also include the step that the mixture after heat treatment is cooled down according to the cooldown rate of 200～1000 DEG C/min。In the present invention, the cooldown rate after heat treatment is 200～1000 DEG C/min。Cooldown rate to choose the enforcement to the present invention critically important because cooldown rate lower than 200 DEG C/min, R^a ₂Fe₁₄The crystallite dimension of B phase and α-Fe phase, for can become thick, is unfavorable for producing stronger spin-exchange-coupled, thus bringing the decline of performance。And cooldown rate is more than 1000 DEG C/min, excessive velocities, it is unfavorable for element R^bEnter R^a ₂Fe₁₄B crystal particle crystal boundary place, forms (R^aR^b)₂Fe₁₄B phase, also increases preparation and puts into。

In a kind of preferred embodiment of the present invention, the cooldown rate of the present invention is 300～600 DEG C/min, within the scope of this cooldown rate, and R^bEasily enter R^a ₂Fe₁₄B phase forms (R at grain boundaries^aR^b)₂Fe₁₄B phase and R^a ₂Fe₁₄B、(R^aR^b)₂Fe₁₄B phase, α-Fe phase crystallite dimension also in the scope of application claims, it addition, within the scope of this cooldown rate, (R^aR^b)₂Fe₁₄B phase is at R^a ₂Fe₁₄Also evenly, coercivity and the remanent magnetism of the magnetic powder so obtained are up to more preferably in the distribution of B crystal particle crystal boundary。

Present invention also offers a kind of bonded permanent magnet, this bonded permanent magnet is formed with binding agent bonding by above-mentioned rare earth permanent magnet powder。The binding agent used in above-mentioned bonded permanent magnet adopts this area conventional binders, for instance it includes but not limited to as nylon, resin, rubber, soft metal。The methods such as preparation method can be passed through to emboss, injection, calendering, extrusion are prepared from, other forms such as prepared bonded permanent magnet can be block, ring-type。Bonded permanent magnet prepared by the present invention has higher remanent magnetism and higher coercivity。

Present invention also offers a kind of device applying above-mentioned bonded permanent magnet, this device has and relatively also has higher coercivity while high magnetic characteristics。

Further illustrate rare earth permanent magnet powder of the present invention below in conjunction with embodiment and comparative example, the beneficial effect of bonded permanent magnet that preparation method comprises it and device。

Describing preparation method in embodiment 1 in detail, in all the other embodiments except parameter difference, preparation method is with embodiment 1。

Embodiment 1

Will according to Nd₁₈Fe_80.2B_1.8Foundry alloy prepared by proportioning is put in crucible; then pass through Medium frequency induction foundry alloy is heated; during existing liquation pending; pass into Ar gas to protect; after alloy forms liquation completely; liquation is made to be ejected into the water-cooled molybdenum wheel of rotation by the BN nozzle of diameter to be 0.4mm, thickness be 5mm; the roughness of molybdenum wheel is 0.1 μm; FFR'S fuel assembly is 15m/s; after aluminium alloy throws away with molybdenum wheel; first being ejected into the copper coin cooling with cooling water, then pass through disintegrating machine and alloy strip crushed, after broken, the particle size of magnetic powder is 60 μm；

TbF by the magnetic powder that particle size is 60 μm after broken and 0.2 μm₃Powder adopts batch mixer mixing according to the mass ratio of 100:15, is put into by mixed powder in heat-treatment furnace and heats, and is wherein argon shield in heat-treatment furnace, and the flow of argon is 0.1m³/ h；Heat treatment temperature is 900 DEG C, and heat treatment time is 1min, and heat treatment heating rate is 10 DEG C/min, after heat treatment terminates, is cooled down according to the rate of cooling of 200 DEG C/min by the mixture after heat treatment；

Magnetic powder sampling after cooling being carried out test analysis, is found by XRD diffraction analysis, magnetic powder has Nd₂Fe₁₄B phase, (NdDy)₂Fe₁₄B and α-Fe phase composition。

The composition of magnetic powder prepared by all the other embodiments is in Table 1, and the preparation condition shown in table 2 and table 3 prepares the rare earth permanent magnet powder of each embodiment, by detecting the performance of the rare earth permanent magnet powder of each embodiment obtained in Table 4。

Table 1:

Table 2: the preparation condition parameter list of each embodiment

Table 3:

Table 4:

The detection method of the roughness of the component analysis of the various embodiments described above, magnetic property, phase structure, crystallite dimension and running roller is as follows:

(1) composition is analyzed test by inductively coupled plasma spectrum generator (ICP)。

(2) magnetic particle capability is characterized by vibrating specimen magnetometer (VSM)。

(3) phase structure in magnetic powder, crystallite dimension are characterized by X-ray diffraction (XRD), and crystallite dimension is calculated by Scherrer formula D=K λ/β cos θ。

(4) the microstructure transmission electron microscope (TEM) of magnetic powder is observed。

(5) roughness of running roller is tested by roughmeter。

As can be seen from the above description, the above embodiments of the present invention achieve following technique effect: the rare-earth magnetic of (1) gained of the present invention, due to Tb₂Fe₁₄B and Dy₂Fe₁₄The anisotropy field of B is Nd respectively₂Fe₁₄3 times of B and 2 times, so (the R of the present invention^aR^b)₂Fe₁₄B phase has high HCJ and an anisotropy field, and nanocrystalline (R^aR^b)₂Fe₁₄B phase and R^a ₂Fe₁₄B phase is the same, generation exchange-coupling interaction of also meeting with α-Fe。So, the magnetic powder of preparation will have remanent magnetism mutually high for α-Fe and (R^aR^b)₂Fe₁₄The coercivity that B phase is high, finally gives nanometer two-phase magnetic powder of high remanent magnetism, high-coercive force。(2) rare earth permanent magnet powder of gained of the present invention, owing to having high coercivity, comparing the operating temperature of Conventional nano two-phase magnetic powder, the magnetic powder of the present invention will have higher operating temperature, adopt nanometer two-phase magnetic powder prepared by present component will significantly widen its application。(3) magnetic powder composition of the present invention and preparation method thereof is used equipment and technique are simple, it is simple to operation, easily realize industrialization。

Further, above-described embodiment 5 is highly preferred embodiment of the present invention, the XRD diffraction pattern of the rare earth permanent magnet powder prepared by Fig. 1 embodiment 5, it will be seen from figure 1 that existing principal phase Nd in the rare earth permanent magnet powder of the present invention₂Fe₁₄B and α-Fe, also has (NdDy)₂Fe₁₄B phase, from its microstructure transmission electron microscope Fig. 2 it can be seen that (NdDy)₂Fe₁₄B phase is distributed in Nd₂Fe₁₄Between B and α-Fe phase (as indicated with an arrow)；From the results shown in Table 4, the magnetic powder prepared by embodiment 5 has the coercivity of higher remanent magnetism and Geng Gao。

The foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, for a person skilled in the art, the present invention can have various modifications and variations。All within the spirit and principles in the present invention, any amendment of making, equivalent replacement, improvement etc., should be included within protection scope of the present invention。

Claims (20)

1. a rare earth permanent magnet powder, it is characterised in that in gross mass 100 parts, the formula of described rare earth permanent magnet powder isWherein, α, β, θ,Mass parts is represented with δ,

Described R^aFor at least one element in Pr, Nd, 18≤α≤27；

Described R^bFor at least one element in Tb, Dy, 0.1≤β≤3；

Described M is one or both elements in Co, Zr, Nb, Ti, Cr, Si, Al, 0≤θ≤5；

Described B is boron element, 0.8≤φ≤1.5,

Described F is fluorine element, 0.05≤δ≤0.1,

The principal phase of described rare earth permanent magnet powder is by R^a ₂Fe₁₄B and α-Fe phase composition；R described in described rare earth permanent magnet powder^bWith (R^aR^b)₂Fe₁₄B phase is distributed in R^a ₂Fe₁₄Between B and α-Fe is biphase。

2. rare earth permanent magnet powder according to claim 1, it is characterised in that 20≤α≤25。

3. rare earth permanent magnet powder according to claim 1, it is characterised in that described R^bFor Dy, and 0.3≤β≤2。

4. rare earth permanent magnet powder according to claim 1, it is characterised in that when described M is element nb and Ti, 0.3≤θ≤2。

5. rare earth permanent magnet powder according to claim 1, it is characterised in that described R^bAt R^a ₂Fe₁₄The concentration of B grain boundary is higher than it at R^a ₂Fe₁₄B intra-die。

6. rare earth permanent magnet powder according to claim 1, it is characterised in that described rare earth permanent magnet powder principal phase R^a ₂Fe₁₄The crystallite dimension of B is 10～50nm, it is preferred to 20～40nm；The crystallite dimension of α-Fe is 10～30nm。

7. the preparation method of the rare earth permanent magnet powder according to any one of a claim 1 to 6, it is characterised in that described preparation method comprises the following steps:

According toProportioning prepareMagnetic powder；

Described in inciting somebody to actionMagnetic powder and R^bF₃Powder mixes, and obtains mixture；

Described mixture is carried out heat treatment, described in obtainingRare earth permanent magnet powder。

8. preparation method according to claim 7, it is characterised in that described inMagnetic powder particle is of a size of 60～200 μm, it is preferred to 80～150 μm。

9. preparation method according to claim 7, it is characterised in that described inMagnetic powder and R^bF₃Powder mixes according to the ratio of mass ratio 100:0.1～5, obtains described mixture；Preferred described mass ratio is 100:0.5～2。

10. preparation method according to claim 9, it is characterised in that described R^bF₃The particle size of powder is 0.01～0.2 μm；It is preferably 0.03～0.1 μm。

11. preparation method according to claim 7, it is characterised in that described heat treated temperature is 400～900 DEG C, the time is 1～30min；Preferred described heat treated temperature is 550～800 DEG C, and the time is 5～15min。

12. preparation method according to claim 11, it is characterised in that the heating rate in described heat treatment process is 10～500 DEG C/min；Preferred described heating rate is 50～200 DEG C/min。

13. preparation method according to claim 12, it is characterised in that after described heat treatment terminates, described in obtainingBefore rare earth permanent magnet powder, also include the step that the mixture after described heat treatment is cooled down according to the cooldown rate of 200～1000 DEG C/min；Preferred described cooldown rate is 300～600 DEG C/min。

14. preparation method according to claim 7, it is characterised in that described according toProportioning prepareThe step of magnetic powder carries out under an argon atmosphere, it is preferable that the flow of passed into argon is 0.1～10m³/h。

15. preparation method according to claim 7, it is characterised in that described according toProportioning prepareThe step of magnetic powder includes:

Will according to describedThe mixed mixed material of proportioning is put in crucible and is heated, and obtains alloy molten solution；

By described alloy molten solution by being arranged on described crucible bottom and coupled nozzle is ejected into the water-cooled running roller of rotation and cools down, obtain cooled alloy band:

Described cooled alloy band is crushed, described in obtainingMagnetic powder。

16. preparation method according to claim 15, it is characterised in that the aperture of described nozzle is 0.4～2mm, thickness is 5～10mm。

17. preparation method according to claim 15, it is characterised in that the rotating speed of preferred described water-cooled running roller is 15～30m/s。

18. preparation method according to claim 15, it is characterised in that the roughness of described water-cooled running roller is 0.1～2 μm。

19. a bonded permanent magnet, it is characterised in that utilize the rare earth permanent magnet powder according to any one of claim 1 to 6 to be prepared from binding agent。

20. a device, it is characterised in that include the bonded permanent magnet described in claim 19。