CN102339670A - Method for manufacturing permanent magnet - Google Patents
Method for manufacturing permanent magnet Download PDFInfo
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- CN102339670A CN102339670A CN2010102316316A CN201010231631A CN102339670A CN 102339670 A CN102339670 A CN 102339670A CN 2010102316316 A CN2010102316316 A CN 2010102316316A CN 201010231631 A CN201010231631 A CN 201010231631A CN 102339670 A CN102339670 A CN 102339670A
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Abstract
The invention provides a method for manufacturing a permanent magnet. The method comprises the step of orientating permanent-magnet alloy powder into a magnetic texture which has powder particles with positive spontaneous magnetic-polarization intensity and powder particles with reversed spontaneous magnetic-polarization intensity in an external magnetic field, wherein the external magnetic field is an alternating magnetic field which has positive magnetic fields and reversed magnetic fields, and the amplitude of magnetic field strength gradually decreases with time, and the frequency is 0.1-100 Hz; and preferably, the amplitude of the magnetic field strength gradually decreases below 5% of the initial amplitude of the magnetic field strength with time, and the frequency is 0.1-60 Hz. The method for manufacturing the permanent magnet has the advantages of high degree of orientation, low cost for manufacture, low energy consumption, high production efficiency and the like.
Description
Technical field
The present invention relates to a kind of manufacture method of permanent magnet; More particularly; Relate to and a kind ofly have the method for the high performance sintered permanent magnet of high-orientation with low alignment magnetic field manufacturing, such sintered permanent magnet is widely used in various industry and fields such as civilian motor, computer, electro-acoustic element, transducer, automobile, Medical Instruments and industrial automation equipment.
Background technology
The modern permanent magnet that is widely used in all kinds of motors, computer, electroacoustic, Medical Instruments, automobile sensor and various industry and fields such as civilian instrument, equipment mainly comprises sintered Nd-Fe-B, Sm-Co and Sr (Ba) based ferrite made from powder metallurgy process.A the most outstanding characteristic of these permanent magnets is: the inner crystal grain of magnet has strong monadic magnetocrystalline anisotropy.So-called monadic magnetocrystalline anisotropy is meant that crystal is magnetized along a certain crystalline axis direction the most easily, then is difficult to be magnetized along other crystalline axis direction relatively.The crystalline axis direction that is magnetized the most easily is called easy magnetizing axis, is called for short to be prone to axle; The most difficult crystalline axis direction that is magnetized is called hard axis, is called for short hard axis.The theory and practice of ferromagnetics proves, no matter is which crystallographic axis, is identical along the positive direction and the reciprocal magnetization characteristic of this crystallographic axis.That is to say, to have two directions of easy axis that differ 180 ° of angles along its easy magnetizing axis for crystal with monadic magnetocrystalline anisotropy, along the direction magnetization that is prone to axle with along its magnetic reversal be equivalence fully.Under the effect of outside magnetic field, the crystal with monadic magnetocrystalline anisotropy can rotate towards magnetic direction, makes its easy axis direction consistent with magnetic direction, and this moment, the energy of system was in minimum state.
As known in the art, for obtaining excellent permanent magnetism performance, need alloyed powder be broken to micron-sized yardstick, then powder is placed on the green briquette that is pressed into definite shape in the die cavity of executing magnetic field outward.In this operation, it is prone to axle along the magnetic direction arrangement under the effect of all powder particle outside magnetic field, applies enough big press power immediately and makes this aligning of powder particle be fixed up, to obtain optimum permanent magnetism performance.Make that it is prone to process that axle is arranged along magnetic direction under the effect of powder particle outside magnetic field, be called the orientation of magnetic.Subsequently,, make it densification, become the magnet blank compressed green body piece sintering at a certain temperature; Also need in case of necessity the blank magnet is carried out temper at a certain temperature, with further optimization magnetic property; Operation then is to carry out machining, and the blank magnet is cut, is trimmed to required shape, size, also need carry out surfacecti proteon in case of necessity and handle; At last, magnetize along direction of easy axis and promptly obtain operable permanent magnet product.
In above-mentioned technology, alloyed powder is broken to micron-sized yardstick after, all powder particles all become monocrystal.The theory and practice of ferromagnetics proves do not having under the situation of external magnetic field, and for reducing the self-demagnetization ability, all there are several magnetic domains in each powder particle inside that is monocrystalline.Shown in accompanying drawing 1 (a), have the crystal of monadic magnetocrystalline anisotropy, its magnetic domain is lath-shaped, and spontaneous magnetic polarization is separated by domain wall between the adjacent magnetic domain along the easy axis direction of crystal, and the spontaneous magnetic polarization of adjacent magnetic domain is reverse each other.Execute outside under the effect of magnetostatic field, the magnetic domain in the powder particle can receive the effect of a moment Γ, and its size is:
Γ＝VJ
sHsinθ. (1)
In the formula, V is the volume of magnetic domain, J
sBe the spontaneous magnetic polarization of alloy, H is the intensity of external magnetic field, and θ is J
sAnd the angle between the H.Can find out from this formula, only if the spontaneous magnetic polarization J of all magnetic domains in the alloy powder particle
sConsistent with the direction of external magnetic field intensity H (θ=0) makes it be prone to axle towards outer magnetic field direction rotating moment Γ otherwise particle always receives one.Therefore, under the effect of outside magnetic field, for reducing the magnetostatic energy of system, a plurality of little magnetic domain of monocrystal granule interior can be merged into an integral body earlier, becomes the single magnetic domain body.At this moment, if powder particle does not have constraint and can freely rotate, just can be with the form rotation of single magnetic domain body, it is consistent with outer magnetic field direction to make it be prone to axle.The magnetic texture arrangement mode of the powder particle in the pressed compact that so, finally obtains is shown in accompanying drawing 1 (b).The neat degree that this specialty is arranged the magnetic texture of the powder particle in the pressed compact is called the degree of orientation of pressed compact magnet.
Yet, always can have the constraint of various complicated mechanical between the powder particle and hinder it and freely rotate.Make powder particle obtain the high as far as possible degree of orientation for overcoming these resistances; The method that generally adopts at present is: execute static magnetic field strength (shown in formula (1) outside increasing as much as possible; Magnetic field intensity H is big more; The suffered turning moment of powder particle is just big more), make the orientation external magnetic field that acts on powder greater than 1.2T, in the hope of obtaining good permanent magnetism performance usually.In narration of the present invention, the orientation external magnetic field belongs to the engineering high-intensity magnetic field, and magnetic field intensity adopts the custom T of unit (tesla) for a long time on the engineering, rather than international unit A/m (amperes per meter), and the conversion mode of the two is in free space: 1T=1 * 10
7/ (4 π) A/m, purpose is in order more succinctly, clearly to set forth content of the present invention.
Traditional operation principle about the magnetic field orientating pressure-type process of making permanent magnet is shown in the accompanying drawing 2.By the current-carrying coil 4 generation magnetic fields of pair of series, form magnetic loop through a pair of cartridge 3 and yoke 2, between symmetrically arranged a pair of cartridge 3, form working gas gap magnetic field; In accompanying drawing 2, with dashed lines and arrow are represented the path and the direction of described magnetic loop respectively.Through described air-gap field, make to place the alloy powder 6 in the former 8 to be orientated along magnetic direction, this magnetic field is called alignment magnetic field; Then, through upper punch 5 and low punch 9 upperpush rod 7 is passed to alloy powder 6 with 1 applied pressure P of down-pressed pole, with alloy powder 6 compression mouldings.In this process, the intensity of the alignment magnetic field of the alloy powder that imposes on 6 is usually up to 1.2～2.1T, and press power P is usually up to 1～5 ton/cm
2, make the magnetic texture that align of alloy powder 6 in said alignment magnetic field be fixed up, form the orientation pressed compact.Subsequently, in coil 4, charge into a less reverse current to produce a less opposing magnetic field, described orientation pressed compact is implemented demagnetization, like this, pressed compact just can be taken out and the sintering operation of implementing next step safely easily.Here lay special stress on is pointed out; In said process; Usually the alignment magnetic field that is applied all is to use the magnetic field of single direction, and such magnetic field with single direction is shown in accompanying drawing 3, and no matter this magnetic field is the magnetic field of the static form shown in accompanying drawing 3 (a) or the magnetic field of the alternation form shown in accompanying drawing 3 (b); Before the orientation pressed compact was implemented demagnetization, the spontaneous magnetic polarization with alloy powder particle that all can only obtain shown in accompanying drawing 1 (b) was the magnetic texture that single direction is arranged.
In above-mentioned orientation die mould process, impose on the direction of the pressure P of alloy powder 6, vertical each other with the direction of the magnetic field intensity that imposes on alloy powder 6, this specialty is called vertical orientated die mould method, is called for short vertical platen press.If with the mode shown in accompanying drawing 4, impose on the direction of the pressure P of alloy powder 6, be parallel to each other with the direction of the magnetic field intensity that imposes on alloy powder 6, this specialty is called parallel-oriented die mould method, is called for short parallel platen press.In accompanying drawing 4, by the current-carrying coil 4 generation magnetic fields of pair of series, coil 4 places the periphery of upperpush rod 7 and down-pressed pole 1, forms two parallelly connected magnetic loops with the yoke 2 of annular; Therefore, upperpush rod 7 plays dual parts cartridge simultaneously and exerts pressure with down-pressed pole 1; At this moment, pass to the pressure P of alloy powder 6, be parallel to each other with the direction of the magnetic field intensity in alloy powder 6 spaces of living in through upper punch 5 and low punch 9.Other principle of parallel platen press is identical with vertical platen press.In parallel pressure process, because that pressure P is ordered about the alloy powder travel direction is parallel with the direction of alignment magnetic field, this is just feasible to depart from magnetic direction along the part powder particle of magnetic direction marshalling; Therefore, under the identical situation of other condition, what the degree of orientation of the permanent magnet of parallel platen press made can be than vertical platen press is low, thereby remanent magnetism, magnetic energy product are low.But parallel platen press has many advantages, more easily with powder directly be pressed into special shape, realize high efficiency, automated job, in this area and vertical platen press by the while extensive use.
Said as preamble; Always can there be various complicated mechanical constraints between the powder particle and hinder its free rotational alignment in magnetic field; For obtaining excellent permanent magnetism performance, the orientation external magnetic field intensity that acts on powder should be greater than 1.2T, and magnetic field intensity is high more; The degree of orientation of powder particle in pressed compact is good more, and the magnetic property of the permanent magnet of made is just high more.Yet as known in the art, the magnetic field intensity that coil produced is directly proportional with the number of ampere turns of coil, obtain the above high-intensity magnetic field of 1.2T, need in bulky coil, import thousands of amperes electric current.Be the huge Joule heat burning apparatus of avoiding coil to produce, the built-in water-cooling system that also has in the coil, this just makes that usually used coil system is bulky, heavy, energy consumption is high, device fabrication is with high costs.And the coil of work under the high-intensity magnetic field state more than the 1.2T need bear huge electromagnetic force and impact between its circle and the circle, is easy to cause that the insulating barrier between the copper cash is destroyed burning apparatus in the coil, causes that maintenance cost is high, operating efficiency is inferior.
Summary of the invention
The present invention is directed against the deficiency of prior art and proposes.Main purpose of the present invention provides the method that the low alignment magnetic field of a kind of usefulness is made the permanent magnet of high-orientation, has that the degree of orientation is even, equipment volume is little, energy consumption is low, a long service life, production efficiency advantages of higher.
The low alignment magnetic field of usefulness of the present invention is made the method for the permanent magnet of high-orientation; Be based on such the principles of science: for crystal with monadic magnetocrystalline anisotropy; Have two directions of easy axis that differ 180 ° of angles along its easy magnetizing axis, along the direction magnetization that is prone to axle with along its magnetic reversal be equivalence fully.That is to say; In the process of orientation die mould; Alloy powder particle is made into the powder particle of the spontaneous magnetic polarization of the existing forward shown in accompanying drawing 5; The magnetic texture that the powder particle of reverse spontaneous magnetic polarization is arranged again, with the magnetic texture of the powder particle that is made into the traditional spontaneous magnetic polarization of having only single direction shown in accompanying drawing 1 (b), the magnetic of both permanent magnets of made behind die mould, sintering is equivalence fully.For the purpose of clear and definite; In the accompanying drawing 5 with the magnetic texture in the process of orientation die mould of the present invention in common magnetic texture shown in accompanying drawing 1 (b) in the different powder particle dot, the spontaneous magnetic polarization of powder particle is in the opposite direction in the spontaneous magnetic polarization direction of these powder particles and the common magnetic texture.That is to say; The method of the permanent magnet of manufacturing high-orientation of the present invention; Be in the process of orientation die mould, alloy powder particle is made into the powder particle of the spontaneous magnetic polarization of existing forward, the magnetic texture of the powder particle of reverse spontaneous magnetic polarization is arranged again.
The worker of this area should be understood that; In the process of existing orientation die mould technology; All be to use the outer alignment magnetic field of executing of the single direction shown in accompanying drawing 3; No matter this magnetic field is static or alternation, and the spontaneous magnetic polarization with alloy powder particle that all can only obtain shown in accompanying drawing 1 (b) is the magnetic texture that single direction is arranged.In case orientation die mould process is accomplished; Pressed compact is applied outer counter again to demagnetizing field; Because the coercive force of alloy powder particle is lower, the spontaneous magnetic polarization of alloy part powder particle just can be reverse, forms the pressed compact of the magnetic texture shown in the similar accompanying drawing 5; Thereby realize the demagnetization to pressed compact, being convenient to pressed compact can be taken out and the sintering operation of implementing next step safely easily.And the powder particle that pressed compact is made into the spontaneous magnetic polarization of existing forward of the present invention; The magnetic texture that the powder particle of reverse spontaneous magnetic polarization is arranged again; Be in the process of orientation die mould, to form, after the orientation die mould is accomplished, need do not resemble and apply the operation of outer counter again the conventional method to demagnetizing field; Pressed compact itself has been in demagnetized state or weak magnetic state, can take out pressed compact easily and implement next step sintering operation safely.
Can know by the ferromagnetics theory and practice; Shown in accompanying drawing 1 (b), has the alloy powder particle that spontaneous magnetic polarization is the magnetic texture that single direction arranges with conventional method orientation; Have very strong self-demagnetizing field,, and keep this spontaneous magnetic polarization to be the magnetic texture that single direction is arranged for the easy axle that makes all powder particles turns to outer magnetic field direction; Execute magnetic field outward except will overcoming the mechanical constraint between the powder particle, also must overcome the self-demagnetizing field of alloy powder particle.Here it is with conventional method when being orientated, and for obtaining the alloy powder pressed compact of the good degree of orientation, must use the one of the main reasons greater than 1.2T orientation external magnetic field intensity.And it is of the present invention in the process of orientation die mould; Alloy powder particle is made into the magnetic texture shown in accompanying drawing 5; Owing to there is the mutual antiparallel particle of a large amount of spontaneous magnetic polarizations; Form another the local little magnetic loop of a part that is dispersed throughout whole powder area between these particles and the particle, its total self-demagnetizing field is almost nil.Like this; With of the present invention the orientation die mould process in; Alloy powder particle is made into has each other antiparallel magnetic texture shown in accompanying drawing 5 of spontaneous magnetic polarization direction, can reduce significantly just obtain the required outer magnetic field intensity of executing of alloy powder pressed compact of high-orientation.
According to a preferred aspect of the present invention, described outer to execute magnetic field be existing forward magnetic field, the alternating magnetic field of opposing magnetic field is arranged again, and the amplitude of magnetic field intensity reduces gradually in time, and frequency is 0.1～100Hz; The amplitude of further preferred magnetic field intensity is decreased to below 5% of its initial amplitude in time gradually, and frequency is 0.1～50Hz.
According to another preferred aspect of the present invention; Described existing forward magnetic field; Have the alternation of opposing magnetic field to execute coil or the single coil generation of magnetic field by a plurality of series connection outward again, the yoke formation magnetic loop through cartridge that places the magnetic conductivity in the coil and the magnetic conductivity that is connected said cartridge forms working gas gap magnetic field in the air gap of said magnetic loop; Exert pressure to the mould that places in the said working gas gap magnetic field space through press, to loading the moulding of exerting pressure of alloy powder in said mould.
Preferably, described existing forward magnetic field, having the alternation of opposing magnetic field to execute magnetic field outward again is to apply once or repeat to apply repeatedly in pressing process.
Preferably, described press applies and passes to the existing forward magnetic field in direction and the said working gas gap magnetic field space of pressure of alloy powder, and there have the alternation of opposing magnetic field to execute the direction in magnetic field outward again to be vertical or parallel.
Preferably, described mould is made up of former, upper punch and low punch three parts, and the relative motion of upperpush rod and down-pressed pole through said press passes to upper punch and low punch with pressure and comes being in the moulding of exerting pressure of alloy powder in the said mould.
According to another preferred aspect of the present invention, the former of said mould is an integral body of being made by weak magnetic material, or is combined by the pole plate of weak magnetic and the side plate of weak magnetic.
Preferably, the former of said mould, upper punch and low punch are that the high-abrasive material with weak magnetic is made.
According to another preferred aspect of the present invention, make the yoke of said cartridge and the magnetic conductivity that is connected said cartridge, all be to be made with soft magnetic material, said soft magnetic material comprises carbon steel, pure iron, silicon steel, permalloy, non-crystaline amorphous metal; Making said former, upper punch and low punch, all is that the high-abrasive material with weak magnetic is made, and the high-abrasive material of said weak magnetic comprises carbide alloy, no magnetic mould steel, pottery etc.
Preferably; The permanent magnet pressed compact of made according to the present invention, with vacuum furnace 900～1200 ℃ of sintering make said pressed compact densification, again through 450～900 ℃ of tempering with optimize magnetic property, with after machinings such as cutting, grinding be trimmed to required geometry with size, in case of necessity also carry out the surfacecti proteon processing, magnetize into the permanent magnet product of required polarity at last; Described vacuum furnace comprises the air-quenching furnace of resistance heating mode and with the air-quenching furnace of microwave heating.
The present invention also provides a kind of permanent magnet product that comprises aforesaid making sintered Nd-Fe-B, Sm-Co, Sr (Ba) based ferrite.
The present invention have degree of orientation height, magnetic property evenly, low cost of manufacture, production efficiency advantages of higher.
Description of drawings
To combine accompanying drawing to explain that embodiment of the present invention is with further elaboration principle of the present invention below.
Fig. 1 (a) is illustrated under the situation that does not have external magnetic field, be to reduce self-demagnetization can, all there is the sketch map of several magnetic domains in each powder particle inside that is monocrystalline;
Fig. 1 (b) expression is with the outer alignment magnetic field of executing of common single direction, and the spontaneous magnetic polarization with alloy powder particle that obtains is the sketch map of the magnetic texture of single direction arrangement;
Fig. 2 representes the side cutaway view of common vertical platen press device operation principle;
The outer Changing Pattern of executing alignment magnetic field of the static state of the single direction that Fig. 3 (a) expression is common;
The outer Changing Pattern of executing alignment magnetic field of the alternation of the single direction that Fig. 3 (b) expression is common;
Fig. 4 representes the side cutaway view of common parallel platen press device operation principle;
The powder particle of the spontaneous magnetic polarization of the existing forward that Fig. 5 representes to make according to the principle of the invention has the magnetic texture of pressed compact of the powder particle of reverse spontaneous magnetic polarization again;
Fig. 6 representes the top plan view according to the device of the permanent magnet product of the low alignment magnetic field manufacturing of the usefulness high-orientation of first embodiment of the invention;
Fig. 7 representes according to the existing forward of applying of first embodiment of the invention magnetic field the Changing Pattern of the alternating magnetic field of opposing magnetic field is arranged again;
Fig. 8 representes the top plan view according to the device of the permanent magnet product of the low alignment magnetic field manufacturing of the usefulness high-orientation of second embodiment of the invention;
Fig. 9 representes according to the existing forward of applying of second embodiment of the invention magnetic field the Changing Pattern of the alternating magnetic field of opposing magnetic field is arranged again.
Figure 10 representes the top plan view according to the device of the permanent magnet product of the low alignment magnetic field manufacturing of the usefulness high-orientation of third embodiment of the invention;
Figure 11 representes the side cutaway view according to the device of the permanent magnet product of the low alignment magnetic field manufacturing of the usefulness high-orientation of fourth embodiment of the invention;
In accompanying drawing 3, accompanying drawing 7 and accompanying drawing 9, abscissa express time, ordinate are represented the size of magnetic field intensity; And represent forward magnetic field with+H, represent the opposing magnetic field with-H.
Embodiment
Specify the preferred embodiment of making the permanent magnet product of high-orientation according to the low alignment magnetic field of usefulness of the present invention below with reference to accompanying drawings.In the accompanying drawings, 1 expression down-pressed pole, the yoke of 2 expression magnetic conductivity, a pair of cartridge of 3 expression magnetic conductivity; The a pair of coil of 4 expression series connection, 5 expression upper punchs, 6 expression alloy powder districts, 7 expression upperpush rods; 8 expression formers, 9 expression low punches, 10 expressions are with the yoke of silicon steel sheet closed assembly, and 11 expressions are with a pair of cartridge of silicon steel sheet closed assembly; 12 expressions produce the coil of the pair of series of alternating magnetic field of the present invention, the side plate of 13 expression formers, 14 expressions alloy powder of the present invention district, the pole plate of 15 expression formers; 16 expressions are used to produce the external alternating source of alternating magnetic field of the present invention, 17 expressions former of the present invention, 18 expressions down-pressed pole of the present invention; 19 expressions upperpush rod of the present invention, 20 expressions upper punch of the present invention, 21 expressions low punch of the present invention.
Embodiment one
Accompanying drawing 6 expressions are according to the top plan view of the device of the permanent magnet product of the low alignment magnetic field manufacturing of the usefulness high-orientation of first embodiment of the invention.Here, press be applied to alloy powder district 14 through upperpush rod, down-pressed pole, upper punch and low punch the direction of pressure P perpendicular to paper; Because compression system and upperpush rod, down-pressed pole, upper punch and the low punch of press belong to routine techniques, set forth the present invention for the sake of simplicity in a capsule, reach here and all omitted it in the top plan view of later embodiment and illustrate.The magnetic field that is produced by coil 12 forms magnetic loop through the yoke 10 of magnetic conductivity with a pair of cartridge 11; Shown in the dotted line of the arrow that superposeed among the figure; The air gap in the middle formation work magnetic field of a pair of cartridge 11 thus, the former of being made up of pole plate 15 and side plate 13 places among the air gap of described magnetic field.In down-pressed pole and low punch move up to the former of being made up of pole plate 15 and side plate 13 and after sealing the lower port of former, evenly the filling percentage by weight is 22%Nd in the former, 6%Pr; 4%Dy, 1%B, 1%Co; 0.1%Cu, 0.3%Al, 0.15%Ga; All the other are the Nd-Fe-B alloy magnetic powder of Fe, and its average particle size is 3.6 μ m.Then, upperpush rod and upper punch move downward, and after the port of sealing former, stop action, and this moment, alloy magnetic powder was closed in the zone 14.Then, in coil 12,, in alloy powder district 14, form existing forward magnetic field as shown in Figure 7, the alternating magnetic field of opposing magnetic field is arranged again through alternating source equipment 16 input currents.The initial amplitude of magnetic field intensity is 0.3T, and the amplitude of magnetic field intensity reduces in time gradually, and frequency is 3Hz, and the amplitude of magnetic field intensity is decreased to 0 after 3 seconds kinds; In this process, the alloy magnetic powder in the zone 14 forms the magnetic powder particle of the spontaneous magnetic polarization of existing forward as shown in Figure 5 under the effect of said alternating magnetic field, the magnetic texture of the magnetic powder particle of reverse spontaneous magnetic polarization is arranged again.
Explanation in passing of the present inventionly forms existing forward magnetic field as shown in Figure 7 in alloy powder district 14, the alternating magnetic field of opposing magnetic field is arranged again, in frequency is 0.1～100Hz scope, all can form effective orientation to alloy powder; If frequency is greater than 100Hz, the initial amplitude of formed alternating magnetic field intensity will be difficult to improve in alloy powder district 14, and the caloric value of magnetic circuit system is also very big, will be relatively poor to the orientation effect of alloy powder; If frequency is less than 0.1Hz, then alloy powder being formed the required time of effective orientation will be very long, and production efficiency will be lower; The preferred frequency range of the present invention is 0.1～50Hz.
Input current produces in the described alternating magnetic field in to coil 12, and upperpush rod and upper punch move downward, and down-pressed pole and low punch move upward, and the alloy magnetic powder in the zone 14 is applied 2000kg/cm
2Vertical pressure make it moulding, and, have the magnetic texture of the magnetic powder particle of reverse spontaneous magnetic polarization to remain in the pressed compact again with the magnetic powder particle of the spontaneous magnetic polarization of described existing forward.Then; Upperpush rod, upper punch, down-pressed pole, low punch move upward together with pressed compact synchronously; Pressed compact is upwards released the upper end of former, and this moment, down-pressed pole stopped action with low punch, and upperpush rod and upper punch continue to move upward to can be with till the taking-up of magnetic pressed compact.Here point out emphatically; The initial amplitude of the alternating magnetic field intensity that embodiments of the invention applied is 0.3T, and the amplitude of magnetic field intensity reduces in time gradually, and frequency is 3Hz; The amplitude of magnetic field intensity is decreased to 0 after 3 seconds; Formed the magnetic powder particle of the spontaneous magnetic polarization of existing forward as shown in Figure 5 this moment in the pressed compact, the magnetic texture of the magnetic powder particle of reverse spontaneous magnetic polarization is arranged again, and the clean magnetic polarization of pressed compact is zero; Externally do not show magnetic, can take out and implement next step sintering operation safely from the former port.The amplitude of the preferred magnetic field intensity of the present invention is decreased to below 5% of its initial amplitude in time gradually; This moment, the clean magnetic polarization of pressed compact was very low; The magnetic that is externally shown very a little less than, be enough to take out and implement from the port of former safely next step sintering operation.If what the amplitude of said magnetic field intensity was decreased to its initial amplitude in time gradually just stops to apply of alternating magnetic field more than 5%; Then because the coercive force of alloy powder particle is lower; Pressed compact just can produce stronger remanent magnetism, takes out pressed compact and its sintering operation of implementing next step is just produced pressed compact easily cracked from the former port.
In above-mentioned orientation die mould process, impose on the direction of the pressure P of alloy powder 14, vertical each other with the direction of the alternating magnetic field intensity that imposes on alloy powder 14, form vertical platen press.
Here point out emphatically once more; The professional of this area should be understood that in the process of the orientation die mould of prior art, the outer orientation static magnetic field of executing that uses single direction is shown in Fig. 3 (a); The alternating magnetic field of single direction is then shown in Fig. 3 (b); They and of the present inventionly apply existing forward magnetic field as shown in Figure 7, the alternating magnetic field of opposing magnetic field is arranged again, be diverse.
Above-mentioned Nd-Fe-B magnetic pressed compact is positioned in the vacuum air-quenching furnace; Sinter at 1040 ℃ and to be of a size of: length 50mm; Width 50mm, the compactness magnet of orientation height 26mm, after 480 ℃ of tempering, obtaining remanent magnetism again is 1.30T; HCJ is 22.3kOe, and maximum magnetic energy product is the permanent magnet of 40.6MGOe.If use the outer orientation static magnetic field of executing of the single direction of the routine shown in Fig. 3 (a), the magnetic field intensity peak value need reach more than the 1.6T, can produce the Nd-Fe-B permanent magnet of equal magnetic property.This shows, use principle of the present invention, can use low alignment magnetic field to make the excellent permanent magnet product of magnetic property of high-orientation.Like this, because the required number of ampere turns of coil significantly reduces, the volume of coil system, weight, energy consumption and device fabrication cost all are able to reduce significantly.
In the present embodiment, preferably use the yoke 10 and cartridge 11 of the magnetic conductivity of silicon steel sheet closed assembly, to reduce the eddy current of magnetic circuit system.The professional of this area should be understood that, in the periphery of the yoke 10 of the magnetic conductivity of silicon steel sheet closed assembly and cartridge 11 and protective sleeve must be installed is well-known knowledge to improve its mechanical strength in the periphery of coil 12; In addition; It also is known in the art on the relevant die frame that the former of being made up of pole plate 15 and side plate 13 must be installed in; Having omitted the diagram of said protective sleeve and relevant die frame member and detailed explanatory note in an embodiment of the present invention is in order to set forth the core content of principle of the present invention more compactly, and this does not limit any claim scope of the present invention.In addition, described upper punch, low punch and carbide alloy or the ceramic material of preferably using weak magnetic by the former that pole plate 15 and side plate 13 are formed.
Embodiment two
Fig. 8 representes the top plan view according to the device of the permanent magnet product of the low alignment magnetic field manufacturing of the usefulness high-orientation of second embodiment of the invention.Compare with first embodiment; The yoke 10 of present embodiment is the annular yoke of a sealing; Cartridge 11 is in the symmetric position in the annular yoke 10 with coil 12; The cartridge 11 of the magnetic field that is produced by coil 12 through a pair of magnetic conductivity and yoke 10 form two parallelly connected magnetic loops of symmetry, shown in the dotted line of the arrow that superposeed in scheming; The air gap in the middle formation work magnetic field of a pair of cartridge 11 thus; The former of being made up of pole plate 15 and side plate 13 places among the air gap of described magnetic field, and such structure is compared the raising of the uniformity that more helps the magnetic field in the alloy powder district 14 with first embodiment; In addition, in coil 12,, in alloy powder district 14, form existing forward magnetic field as shown in Figure 9 through alternating source equipment 16 input currents; The alternating magnetic field that the opposing magnetic field is arranged again; The initial amplitude of magnetic field intensity is 0.2T, and the amplitude of magnetic field intensity reduces in time gradually; Frequency is 6Hz; Whenever the amplitude of magnetic field intensity is decreased to 0 after 1.5 seconds, and then repeats to apply once described alternating magnetic field, just in 3 seconds, has applied continuously twice and embodiment one similar alignment magnetic field; In this process, the magnetic in the alloy powder district 14 forms the magnetic powder particle of the spontaneous magnetic polarization of existing forward as shown in Figure 5 under the effect of said alternating magnetic field, the magnetic texture of the magnetic powder particle of reverse spontaneous magnetic polarization is arranged again.Used Nd-Fe-B alloy magnetic powder and compacting size are all identical with first embodiment with method.In accompanying drawing 8, press is applied to the direction of pressure P in alloy powder district 14 perpendicular to paper through upperpush rod, down-pressed pole, upper punch and low punch, vertical each other with the direction of the alternating magnetic field intensity that imposes on alloy powder 14, forms vertical platen press.
To be positioned in the vacuum air-quenching furnace with the Nd-Fe-B magnetic pressed compact that said method is made; Sinter at 1040 ℃ and to be of a size of: length 50mm; Width 50mm, the compactness magnet of orientation height 26mm, after 480 ℃ of tempering, obtaining remanent magnetism again is 1.31T; HCJ is 21.6kOe, and maximum magnetic energy product is the permanent magnet of 41.3MGOe.In like manner, if use the outer orientation static magnetic field of executing of the single direction of the routine shown in Fig. 3 (a), the magnetic field intensity peak value need reach more than the 1.6T, can produce the Nd-Fe-B permanent magnet of equal magnetic property.This shows, use principle of the present invention, can use low alignment magnetic field to make the excellent permanent magnet product of magnetic property of high-orientation.Like this, because the required number of ampere turns of coil significantly reduces, the volume of coil system, weight, energy consumption and device fabrication cost all are able to reduce significantly.
In the present embodiment, preferably use the yoke 10 and cartridge 11 of the magnetic conductivity of silicon steel sheet closed assembly, to reduce the eddy current of magnetic circuit system.The professional of this area should be understood that, in the periphery of the yoke 10 of the magnetic conductivity of silicon steel sheet closed assembly and cartridge 11 and protective sleeve must be installed is well-known knowledge to improve its mechanical strength in the periphery of coil 12; In addition; It also is known in the art on the relevant die frame that the former of being made up of pole plate 15 and side plate 13 must be installed in; Having omitted the diagram of said protective sleeve and relevant die frame member and detailed explanatory note in an embodiment of the present invention is in order to set forth the core content of principle of the present invention more compactly, and this does not limit any claim scope of the present invention.In addition, described upper punch, low punch,
And carbide alloy or the ceramic material of preferably using weak magnetic by the former that pole plate 15 and side plate 13 are formed.
Because the principle of present embodiment and embodiment one is identical, constitute also similar basically, so omitted detailed description to its pressing process.
Embodiment three
Figure 10 representes the top plan view according to the device of the permanent magnet product of the low alignment magnetic field manufacturing of the usefulness high-orientation of third embodiment of the invention.Compare with first embodiment, the coil 12 of present embodiment is single coil, and coil 12 places the geometry symmetric position of yoke 10, and a pair of cartridge 11 then is in coil 12 outsides, and the two ends with yoke 10 are connected respectively; The magnetic field that is produced by coil 12 forms magnetic loop through the yoke 10 of magnetic conductivity with a pair of cartridge 11, shown in the dotted line of the arrow that superposeed in scheming; The air gap in the middle formation work magnetic field of a pair of cartridge 11 thus, the former of being made up of pole plate 15 and side plate 13 place among the air gap of described magnetic field; In addition, in coil 12,, in alloy powder district 14, form existing forward magnetic field as shown in Figure 9 through alternating source equipment 16 input currents; The alternating magnetic field that the opposing magnetic field is arranged again, the initial amplitude of magnetic field intensity are 0.2T, and; The amplitude of magnetic field intensity reduces in time gradually, and frequency is 6Hz, and the amplitude of magnetic field intensity is decreased to 0 after 1.5 seconds; And then repeat to apply once described alternating magnetic field, just in 3 seconds, applied continuously twice and embodiment one similar alignment magnetic field; In this process, the magnetic in the alloy powder district 14 forms the magnetic powder particle of the spontaneous magnetic polarization of existing forward as shown in Figure 5 under the effect of said alternating magnetic field, the magnetic texture of the magnetic powder particle of reverse spontaneous magnetic polarization is arranged again.Used Nd-Fe-B alloy magnetic powder and compacting size are all identical with first embodiment with method.In accompanying drawing 10, press is applied to the direction of pressure P in alloy powder district 14 perpendicular to paper through upperpush rod, down-pressed pole, upper punch and low punch, vertical each other with the direction of the alternating magnetic field intensity that imposes on alloy powder 14, forms vertical platen press.
To be positioned in the vacuum air-quenching furnace with the Nd-Fe-B magnetic pressed compact that said method is made; Sinter at 1040 ℃ and to be of a size of: length 50mm; Width 50mm, the compactness magnet of orientation height 26mm, after 480 ℃ of tempering, obtaining remanent magnetism again is 1.29T; HCJ is 22.7kOe, and maximum magnetic energy product is the permanent magnet of 40.1MGOe.In like manner, if use the outer orientation static magnetic field of executing of the single direction of the routine shown in Fig. 3 (a), the magnetic field intensity peak value need reach more than the 1.6T, can produce the Nd-Fe-B permanent magnet of equal magnetic property.This shows, use principle of the present invention, can use low alignment magnetic field to make the excellent permanent magnet product of magnetic property of high-orientation.Like this, because the required number of ampere turns of coil significantly reduces, the volume of coil system, weight, energy consumption and device fabrication cost all are able to reduce significantly.
In the present embodiment, preferably use the yoke 10 and cartridge 11 of the magnetic conductivity of silicon steel sheet closed assembly, to reduce the eddy current of magnetic circuit system.The professional of this area should be understood that, in the periphery of the yoke 10 of the magnetic conductivity of silicon steel sheet closed assembly and cartridge 11 and protective sleeve must be installed is well-known knowledge to improve its mechanical strength in the periphery of coil 12; In addition; It also is known in the art on the relevant die frame that the former of being made up of pole plate 15 and side plate 13 must be installed in; Having omitted the diagram of said protective sleeve and relevant die frame member and detailed explanatory note in an embodiment of the present invention is in order to set forth the core content of principle of the present invention more compactly, and this does not limit any claim scope of the present invention.In addition, described upper punch, low punch and carbide alloy or the ceramic material of preferably using weak magnetic by the former that pole plate 15 and side plate 13 are formed.
Because the principle of present embodiment and embodiment one is identical, constitute also similar basically, so omitted detailed description to its pressing process.
Embodiment four
Figure 11 representes the side cutaway view according to the device of the permanent magnet product of the low alignment magnetic field manufacturing of the usefulness high-orientation of fourth embodiment of the invention.Compare with first embodiment, the coil 12 of the pair of series of present embodiment is individually fixed on upperpush rod 19 and the down-pressed pole 18, and upperpush rod 19 passes the yoke 10 of annular with down-pressed pole 18, coil 12 in pressing process along with upperpush rod 19 and down-pressed pole 18 move together; And upperpush rod 19 plays a part to go up cartridge and following cartridge simultaneously with down-pressed pole 18, forms two symmetrical parallelly connected magnetic loops with the yoke 10 of annular, shown in the dotted line of the arrow that superposeed among the figure; At the middle formation work magnetic field air gap of upperpush rod 19 and down-pressed pole 18, former 17 places among the air gap of described magnetic field thus; In coil 12,, in alloy powder district 14, form existing forward magnetic field as shown in Figure 9, the alternating magnetic field of opposing magnetic field is arranged again through alternating source equipment 16 input currents; The initial amplitude of magnetic field intensity is 0.18T, and the amplitude of magnetic field intensity reduces in time gradually; Frequency is 6Hz; Whenever the amplitude of magnetic field intensity is decreased to 0 after 1.5 seconds, and then repeats to apply once described alternating magnetic field, just in 3 seconds, has applied continuously twice and embodiment one similar alignment magnetic field; In this process, the magnetic in the alloy powder district 14 forms the magnetic powder particle of the spontaneous magnetic polarization of existing forward as shown in Figure 5 under the effect of said alternating magnetic field, the magnetic texture of the magnetic powder particle of reverse spontaneous magnetic polarization is arranged again.Used Nd-Fe-B alloy magnetic powder and compacting size are all identical with first embodiment with method.
In said process, the magnetic field that coil 12 is produced is the direction that is parallel to pressure P between upperpush rod 19 and down-pressed pole 18, forms parallel platen press.
To be positioned in the vacuum air-quenching furnace with the Nd-Fe-B magnetic pressed compact that said method is made; Sinter at 1040 ℃ and to be of a size of: length 50mm; Width 50mm, the compactness magnet of orientation height 26mm, after 480 ℃ of tempering, obtaining remanent magnetism again is 1.26T; HCJ is 23.1kOe, and maximum magnetic energy product is the permanent magnet of 38.3MGOe.In like manner, if use the outer orientation static magnetic field of executing of the single direction of the routine shown in Fig. 3 (a), the magnetic field intensity peak value need reach more than the 1.6T, can produce the Nd-Fe-B permanent magnet of equal magnetic property.This shows, use principle of the present invention, can use low alignment magnetic field to make the excellent permanent magnet product of magnetic property of high-orientation.Like this, because the required number of ampere turns of coil significantly reduces, the volume of coil system, weight, energy consumption and device fabrication cost all are able to reduce significantly.
In the present embodiment, preferably use yoke 10, upperpush rod 19 and the down-pressed pole 18 of the magnetic conductivity of silicon steel sheet closed assembly, to reduce the eddy current of magnetic circuit system.The professional of this area should be understood that, in the periphery of the yoke 10 of the magnetic conductivity of silicon steel sheet closed assembly and cartridge 11 and protective sleeve must be installed is well-known knowledge to improve its mechanical strength in the periphery of coil 12; In addition; Must be installed in by former 17 also is known in the art on the relevant die frame; Having omitted the diagram of said protective sleeve and relevant die frame member and detailed explanatory note in an embodiment of the present invention is in order to set forth the core content of principle of the present invention more compactly, and this does not limit any claim scope of the present invention.In addition, described upper punch, low punch and carbide alloy or the ceramic material of preferably using weak magnetic by the former that pole plate 15 and side plate 13 are formed.
The worker of this area should be understood that in each embodiment explained above, the principle of making the permanent magnet product of high-orientation with low alignment magnetic field is identical.In addition,, not only described sintered Nd-Fe-B magnet can be made, also SmCo can be made by the method in each embodiment explained above
5, Sm
2Co
17And the sintered permanent magnet of Sr (Ba) based ferrite.
Specified principle and the method that the low alignment magnetic field of usefulness disclosed according to the present invention is made the permanent magnet product of high-orientation with reference to accompanying drawing above, those skilled in the art can make sintered Nd-Fe-B magnet, SmCo with principle disclosed according to the present invention and method thus
5, Sm
2Co
17And the sintered permanent magnet of Sr (Ba) based ferrite is widely used in various fields; For example be applied to be applied to the driver part of various loud speakers, transducer, electric motor of automobile and various Medical Instruments and industrial automation equipment, instrument etc. in various computer drives, industry and the civilian motor.
Specified a plurality of embodiment of the present invention above, but top embodiment only is to schematic illustration of the present invention and unrestricted the present invention with reference to accompanying drawing.In addition, though above be with separately, the form of separating describes each embodiment, those skilled in the art are to be appreciated that above-mentioned a plurality of embodiment also can use in combination.And those skilled in the art can combine the technology of the manufacturing permanent magnet of existing routine that the present invention is made various modifications and variation after having read above-mentioned explanation, and this modification and variation also drop within protection scope of the present invention.
Claims (10)
1. the manufacture method of a permanent magnet comprises: permanent magnetic alloy powder is executed the powder particle that is orientated to the spontaneous magnetic polarization of existing forward in the magnetic field outside, the magnetic texture of the powder particle of reverse spontaneous magnetic polarization is arranged again; Executing magnetic field outside described, is existing forward magnetic field, the alternating magnetic field of opposing magnetic field is arranged again, and the amplitude of alternating magnetic field intensity reduces gradually in time, and frequency is 0.1～100Hz; The amplitude of further preferred alternating magnetic field intensity is decreased to below 5% of its initial amplitude in time gradually, and frequency is 0.1～60Hz.
2. the manufacture method of permanent magnet according to claim 1; Wherein: described existing forward magnetic field; There is the alternation of opposing magnetic field to execute coil or the single coil generation of magnetic field outward again by a plurality of series connection; Yoke through cartridge that places the magnetic conductivity in the coil and the magnetic conductivity that is connected said cartridge forms magnetic loop; In the air gap of said magnetic loop, form working gas gap magnetic field, exert pressure to the mould that places in the said working gas gap magnetic field space, to loading the moulding of exerting pressure of alloy powder in said mould through press.
3. the manufacture method of permanent magnet according to claim 1 and 2, wherein: described existing forward magnetic field, having the alternation of opposing magnetic field to execute magnetic field outward again is to apply once or repeat to apply repeatedly in pressing process.
4. the manufacture method of permanent magnet according to claim 1 and 2, wherein: described press applies and pass to alternation in direction and the said working gas gap magnetic field space of pressure of alloy powder, and to execute the direction in magnetic field outward vertical perhaps parallel.
5. the manufacture method of permanent magnet according to claim 1 and 2; Wherein: described mould is made up of former, upper punch and low punch three parts; The relative motion of upperpush rod and down-pressed pole through said press passes to upper punch and low punch with pressure and comes being in the moulding of exerting pressure of alloy powder in the said mould.
6. the manufacture method of permanent magnet according to claim 5, wherein: the former of said mould is an integral body of being made by weak magnetic material, or is combined by the pole plate of weak magnetic and the side plate of weak magnetic.
7. the manufacture method of permanent magnet according to claim 5, wherein: the former of said mould, upper punch and low punch are that the high-abrasive material with weak magnetic is made.
8. according to the manufacture method of claim 2 or 5 described permanent magnets; Wherein: make the cartridge of said magnetic conductivity and the yoke of the magnetic conductivity that is connected said cartridge; Be to be made with soft magnetic material, said soft magnetic material comprises carbon steel, pure iron, silicon steel, permalloy, non-crystaline amorphous metal; Said former, upper punch and low punch are that the high-abrasive material with weak magnetic is made, and the high-abrasive material of said weak magnetic comprises carbide alloy, no magnetic mould steel, pottery etc.
9. the manufacture method of permanent magnet according to claim 1 and 2; Wherein: the permanent magnet powder pressed compact of made; With vacuum furnace 900～1200 ℃ of sintering make said pressed compact densification, again through 450～900 ℃ of tempering to optimize magnetic property; With after cutting, abrasive machine processing are trimmed to required geometry and size, carry out surfacecti proteon again and handle, magnetize into the permanent magnet product of required polarity at last; Described vacuum furnace comprises the air-quenching furnace of resistance heating mode and with the air-quenching furnace of microwave heating.
10. permanent magnet that comprises that the said method of claim 1-9 is made.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102316316A CN102339670A (en) | 2010-07-21 | 2010-07-21 | Method for manufacturing permanent magnet |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010102316316A CN102339670A (en) | 2010-07-21 | 2010-07-21 | Method for manufacturing permanent magnet |
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| CN102339670A true CN102339670A (en) | 2012-02-01 |
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| CN102658367A (en) * | 2012-05-16 | 2012-09-12 | 上海大学 | Method and device for preparing high-silicon silicon steel sheet in static magnetic field with powder sintering method |
| CN102773477A (en) * | 2012-08-16 | 2012-11-14 | 俞红霞 | Vacuumizing forming device and method of magnetic field hydraulic machine |
| CN103161400A (en) * | 2013-04-08 | 2013-06-19 | 屈家发 | Electromagnetic impacter |
| CN103240416A (en) * | 2013-05-03 | 2013-08-14 | 浙江中元磁业股份有限公司 | Method and mould for manufacturing NeFeB (Neodymium iron boron) radiation-orientated ring magnet |
| CN105965446A (en) * | 2016-06-29 | 2016-09-28 | 屈家发 | Electromagnetic hammer drill |
| CN113555206A (en) * | 2020-11-11 | 2021-10-26 | 华为杰通（北京）科技有限公司 | Method for establishing target space extremely-weak magnetic field, magnetizing equipment and magnetized product |
| CN114242437A (en) * | 2021-11-15 | 2022-03-25 | 天津三环乐喜新材料有限公司 | Preparation method of high-performance sintered Re-Fe-B system |
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2010
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102658367A (en) * | 2012-05-16 | 2012-09-12 | 上海大学 | Method and device for preparing high-silicon silicon steel sheet in static magnetic field with powder sintering method |
| CN102658367B (en) * | 2012-05-16 | 2014-12-10 | 上海大学 | Method and device for preparing high-silicon silicon steel sheet in static magnetic field with powder sintering method |
| CN102773477A (en) * | 2012-08-16 | 2012-11-14 | 俞红霞 | Vacuumizing forming device and method of magnetic field hydraulic machine |
| CN103161400A (en) * | 2013-04-08 | 2013-06-19 | 屈家发 | Electromagnetic impacter |
| CN103161400B (en) * | 2013-04-08 | 2015-04-22 | 屈家发 | Electromagnetic impacter |
| CN103240416A (en) * | 2013-05-03 | 2013-08-14 | 浙江中元磁业股份有限公司 | Method and mould for manufacturing NeFeB (Neodymium iron boron) radiation-orientated ring magnet |
| CN103240416B (en) * | 2013-05-03 | 2015-01-14 | 浙江中元磁业股份有限公司 | Method and mould for manufacturing NeFeB (Neodymium iron boron) radiation-orientated ring magnet |
| CN105965446A (en) * | 2016-06-29 | 2016-09-28 | 屈家发 | Electromagnetic hammer drill |
| CN113555206A (en) * | 2020-11-11 | 2021-10-26 | 华为杰通（北京）科技有限公司 | Method for establishing target space extremely-weak magnetic field, magnetizing equipment and magnetized product |
| CN113555206B (en) * | 2020-11-11 | 2024-02-02 | 华为杰通（北京）科技有限公司 | Method for establishing extremely weak magnetic field in target space, magnetizing equipment and magnetized product |
| CN114242437A (en) * | 2021-11-15 | 2022-03-25 | 天津三环乐喜新材料有限公司 | Preparation method of high-performance sintered Re-Fe-B system |
| CN114242437B (en) * | 2021-11-15 | 2022-05-24 | 天津三环乐喜新材料有限公司 | Preparation method of high-performance sintered Re-Fe-B system |
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Open date: 20120201 |